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RRB Group D · Flashcards

RRB Group D flashcards

519 cards from 67 fact-checked topic notes · English

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Number System — Mathematics · 8 cards

Natural Numbers (N): Counting numbers starting from 1: {1, 2, 3, 4, ...}. Used for counting discrete objects; no zero, negatives, or fractions.
Whole Numbers (W): Natural numbers plus zero: {0, 1, 2, 3, ...}. Zero represents "nothing" and is the additive identity.
Integers (Z): All whole numbers plus their negatives: {..., -3, -2, -1, 0, 1, 2, 3, ...}. Closed under addition, subtraction and multiplication but not division.
Rational Numbers (Q): Any number expressible as p/q where p and q are integers and q ≠ 0. Includes terminating decimals (0.75 = 3/4) and repeating decimals (0.333... = 1/3). All integers are rational since 5 = 5/1.
Prime Numbers: Natural numbers greater than 1 with exactly two factors: 1 and itself. First ten primes: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29. Note: 2 is the only even prime; 1 is neither prime nor composite.
Composite Numbers: Natural numbers greater than 1 with more than two factors. Examples: 4, 6, 8, 9, 10. Every composite has a unique prime factorization.
Co-prime (Relatively Prime): Two numbers whose HCF is 1. Examples: (8, 15), (21, 25). Co-primes need not be prime themselves.
Place Value System: In decimal notation, each position represents a power of 10. In 5,847: the 7 is in ones place (7×1), 4 in tens (4×10), 8 in hundreds (8×100), 5 in thousands (5×1000).

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BODMAS — Mathematics · 6 cards

BODMAS hierarchy: Always perform operations in this strict order: Brackets first, then Orders (powers and roots), then Division and Multiplication (left to right), finally Addition and Subtraction (left to right). Never work purely left-to-right unless that happens to match BODMAS order.
Division and Multiplication have equal priority: When both appear in an expression, perform them left to right as they occur. The same applies to Addition and Subtraction — equal priority, left-to-right execution. Many errors come from assuming multiplication always precedes division.
Bracket types and priority: Simplify innermost brackets first. The hierarchy is: ( ) parentheses/round brackets first, then { } curly/braces, then [ ] square brackets. Always work inside-out when brackets are nested.
"Of" means multiplication: In Indian exam context, "of" is a multiplication operator. For example, "1/2 of 40" means 1/2 × 40 = 20. This can appear in word problems disguised as BODMAS questions.
Negative signs and brackets: Treat negative signs carefully. -3² means -(3²) = -9, but (-3)² means (-3)×(-3) = 9. The bracket placement changes the result entirely. Always clarify what the negative sign applies to.
Orders (exponents) before multiplication/division: 2 × 3² = 2 × 9 = 18, not 6² = 36. Calculate the power first, then multiply. This is a common error point.

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Decimals and Fractions — Mathematics · 8 cards

Fraction basics: A fraction a/b has numerator a and denominator b (b ≠ 0). Proper fraction: a < b. Improper fraction: a ≥ b. Mixed number: whole number plus proper fraction (e.g. 2 3/5).
Decimal place value: In 12.345, 3 is tenths (1/10), 4 is hundredths (1/100), 5 is thousandths (1/1000). Every decimal is implicitly a fraction with denominator 10, 100, 1000, etc.
Like and unlike fractions: Like fractions share the same denominator (1/7, 3/7). Unlike fractions have different denominators (1/3, 2/5) and require LCM to add or subtract.
Equivalent fractions: Multiplying or dividing numerator and denominator by the same non-zero number yields an equivalent fraction. 2/3 = 4/6 = 6/9.
Terminating vs recurring decimals: Fraction converts to terminating decimal if denominator (in lowest terms) has only factors 2 and/or 5. Otherwise recurring: 1/3 = 0.333..., written 0.3̅.
Operations are reversible: Any decimal can be written as a fraction (0.6 = 6/10 = 3/5), any fraction can be divided to get decimal (3/8 = 0.375). Choose the form that simplifies computation.
Simplification priority: Always reduce fractions to lowest terms before final answer. Use HCF of numerator and denominator.
Alignment in decimal operations: For addition/subtraction, align decimal points vertically. For multiplication, ignore decimal points initially, then count total decimal places in factors and place in product.

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LCM and HCF — Mathematics · 8 cards

HCF (Highest Common Factor): is the largest number that divides all given numbers without leaving a remainder. It represents the "biggest common piece" you can extract from the numbers. Use HCF when the problem asks for maximum size, greatest length, or largest group.
LCM (Least Common Multiple): is the smallest number that is exactly divisible by all given numbers. It represents the first common meeting point. Use LCM when the problem asks for minimum time, shortest distance, or when events repeat together.
Prime Factorization Method: Break each number into prime factors. For HCF, take the lowest power of common primes. For LCM, take the highest power of all primes present.
Division Method (for HCF): Use Euclidean algorithm — repeatedly divide the larger number by the smaller, replace the larger with the remainder, until remainder is zero. The last non-zero divisor is the HCF.
Relation between LCM and HCF: For any two numbers a and b, Product of numbers = LCM × HCF, i.e., a × b = LCM(a,b) × HCF(a,b).
LCM and HCF of fractions: HCF of fractions = (HCF of numerators) / (LCM of denominators). LCM of fractions = (LCM of numerators) / (HCF of denominators).
LCM and HCF of decimals: Convert decimals to fractions (or multiply by 10, 100, etc. to remove decimal), find LCM/HCF, then convert back by dividing by the same power of 10.
Co-prime numbers: Two numbers whose HCF is 1. For co-prime numbers, LCM = product of the numbers.

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Ratio and Proportion — Mathematics · 8 cards

Ratio: expresses the relationship between two quantities of the same kind as a:b or a/b. A ratio of 3:4 means the first quantity is 3 parts for every 4 parts of the second. Ratios have no units and can be simplified like fractions.
Proportion: states that two ratios are equal: a:b = c:d or a/b = c/d. In a proportion, the product of extremes equals the product of means: a×d = b×c. This cross-multiplication property solves most proportion problems in one step.
Compound ratio: is the ratio of products of corresponding terms from two or more ratios. The compound ratio of a:b and c:d is (a×c):(b×d). If ratios are 2:3 and 4:5, compound ratio is (2×4):(3×5) = 8:15.
Direct proportion: (x ∝ y) means if one quantity doubles, the other doubles too. Cost ∝ quantity purchased. Use the relationship x₁/y₁ = x₂/y₂ to solve.
Inverse proportion: (x ∝ 1/y) means if one quantity doubles, the other halves. Workers ∝ 1/time to complete work. Use x₁×y₁ = x₂×y₂.
Duplicate and triplicate ratios: mean squaring or cubing both terms. Duplicate ratio of a:b is a²:b². Triplicate ratio is a³:b³. Sub-duplicate (square root) and sub-triplicate (cube root) ratios reverse this operation.
Partnership: divides profit or loss among partners in the ratio of their (capital × time). If capitals are equal, profit ratio equals time ratio. If time is equal, profit ratio equals capital ratio. For varying capital and time, multiply each partner's contribution to get the ratio.
Continued ratio: a:b:c means a/b and b/c are both maintained. If a:b = 2:3 and b:c = 4:5, convert to common b: a:b:c = 8:12:15.

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Percentage — Mathematics · 7 cards

Definition: Percentage expresses a number as a fraction of 100. If a quantity is x% of another, it means x/100 of that quantity.
Base value matters: "30% of 200" means (30/100) × 200 = 60. Always identify what the percentage is calculated on — the base or reference value.
Percentage increase/decrease: If a value V increases by r%, new value = V × (1 + r/100). If it decreases by r%, new value = V × (1 – r/100).
Successive percentage changes: Two successive changes of a% and b% do NOT simply add. Net effect = a + b + (ab/100). The sign depends on increase (+) or decrease (–).
Reverse percentage problems: If new value after r% increase is N, original value = N/(1 + r/100). Similarly for decrease, original = N/(1 – r/100).
Fraction of one quantity to another: If A is compared to B, then A as a percentage of B = (A/B) × 100%.
Percentage point vs percentage change: A change from 40% to 50% is a 10 percentage point increase but a 25% relative increase (because 10 is 25% of the original 40).

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Mensuration — Mathematics · 8 cards

Perimeter: is the total boundary length of a 2-D figure; measured in linear units (cm, m). Used for fencing, framing, or bordering problems.
Area: is the surface enclosed by a 2-D figure; measured in square units (cm², m²). Common in flooring, painting, and land measurement problems.
Surface Area: is the total outer area of a 3-D object; measured in square units. Two types: Lateral Surface Area (LSA) excludes top/bottom; Total Surface Area (TSA) includes all faces.
Volume: is the space occupied by a 3-D object; measured in cubic units (cm³, m³, liters). Used in tank capacity, material quantity, and liquid problems.
Composite Figures: combine two or more basic shapes. Break them into recognizable parts, calculate separately, then add or subtract as needed.
Unit Conversion: is critical: 1 m = 100 cm; 1 m² = 10,000 cm²; 1 m³ = 1,000,000 cm³; 1 liter = 1,000 cm³. Always convert to the same unit before calculation.
π (Pi): is approximately 22/7 or 3.14. Use 22/7 when numbers are multiples of 7 for easier calculation; use 3.14 otherwise.
Pythagoras theorem: (a² + b² = c²) is often needed to find missing dimensions in right triangles before applying mensuration formulas.

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Time and Work — Mathematics · 8 cards

Work as a quantity: Total work can be assigned any convenient value—commonly 1 unit or 100%. If A finishes a job in 10 days, A's one-day work = 1/10 of the job.
Rate (efficiency) = Work / Time: If efficiency is constant, work done is directly proportional to time spent. Doubling workers (assuming same efficiency) halves the time.
Man-Days or Work-Units: Total work = Number of persons × Days × Hours per day. Adjust this product when comparing different groups: 6 men in 8 days = 48 man-days of work.
Inverse proportion for time: If work is constant, Time ∝ 1/Number of workers. If 5 workers take 12 days, 10 workers take 6 days (assuming equal efficiency).
Combined work rate: When A and B work together, their one-day combined work = (A's rate) + (B's rate). If A does 1/x per day and B does 1/y per day, together they do (1/x + 1/y) = (x+y)/(xy) per day.
Pipes and cisterns analogy: Inlet pipe = positive work (filling); outlet/leak = negative work (emptying). Net rate = sum of all rates with appropriate signs.
Efficiency ratio: If efficiencies are in the ratio m:n, then times taken are in the ratio n:m (inverse). If A is twice as efficient as B, A takes half the time B takes.
Partial work and remainder: If part of the work is done, subtract that fraction from 1 to find remaining work. Then apply rates to the remainder.

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Time and Distance — Mathematics · 7 cards

Fundamental Relationship: Distance = Speed × Time. Rearrange to find any one quantity if two are known: Speed = Distance/Time, Time = Distance/Speed.
Unit Conversion: 1 km/h = 5/18 m/s and 1 m/s = 18/5 km/h. Always check units in word problems and convert as needed before calculation.
Relative Speed: (same direction): When two objects move in the same direction, their relative speed = |Speed₁ - Speed₂|. Used when one overtakes the other.
Average Speed: For a journey with different speeds over equal distances, Average Speed = Total Distance / Total Time, NOT the arithmetic mean of speeds.
Trains Crossing: When a train crosses a stationary object (pole, man), distance = length of train. When crossing a platform or bridge, distance = length of train + length of platform/bridge.
Boats and Streams: Downstream speed = speed of boat in still water + speed of stream. Upstream speed = speed of boat in still water - speed of stream. Use these to find boat speed and stream speed separately.
Meeting and Chasing: If two objects start simultaneously and move towards each other, time to meet = distance between them / (sum of speeds). If one chases the other, time to meet = initial gap / (difference of speeds).

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Simple and Compound Interest — Mathematics · 7 cards

Simple Interest (SI): is interest calculated only on the original principal throughout the loan/investment period. It grows linearly—if you invest ₹1000 at 10% SI for 3 years, you earn ₹100 each year, totaling ₹300.
Compound Interest (CI): is interest calculated on the principal plus accumulated interest from previous periods. The interest "compounds" or multiplies. The same ₹1000 at 10% CI for 3 years earns ₹100 in year 1, ₹110 in year 2, and ₹121 in year 3, totaling ₹331.
Principal (P): is the original sum of money borrowed or invested. Rate (R) is the percentage interest per time period (usually per year). Time (T) is the duration for which money is borrowed or invested, expressed in years unless stated otherwise.
Amount (A): is the total money returned at the end—it equals Principal + Interest. For SI: A = P + SI. For CI: A = P(1 + R/100)^T.
Compounding frequency: matters for CI. Annual compounding applies interest once per year. Half-yearly compounding applies interest twice per year (rate becomes R/2, time becomes 2T). Quarterly compounding uses R/4 and 4T.
Difference between SI and CI: for the same P, R, T is a common question type. For 2 years: CI - SI = P(R/100)². For 3 years: CI - SI = P(R/100)²(3 + R/100). These derived formulas save time.
Instalment problems: involve paying back a loan in equal periodic payments. Each instalment covers both principal and interest. The key formula: if instalments of x are paid for n years at R% SI, then P = x × [100n + n(n−1)R/2]/(100 + nR).

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Profit and Loss — Mathematics · 7 cards

Cost Price (CP): is the price at which an article is purchased or the total expense incurred to acquire/produce it. All profit or loss calculations reference this base value.
Selling Price (SP): is the price at which an article is sold to the buyer. The relationship between SP and CP determines whether there's profit or loss.
Profit: occurs when SP > CP; the profit amount is (SP − CP), and the profit percentage is always calculated on the Cost Price: Profit % = [(SP − CP)/CP] × 100.
Loss: occurs when SP < CP; the loss amount is (CP − SP), and loss percentage is Loss % = [(CP − SP)/CP] × 100, again based on Cost Price.
Marked Price (MP): is the label price or list price printed on an article before any discount is applied; it's typically higher than the seller's intended selling price.
Discount: is the reduction offered on the Marked Price. Discount amount = MP − SP, and Discount % = [(MP − SP)/MP] × 100, calculated on Marked Price.
Successive Discounts: are multiple discounts applied one after another. Two discounts of x% and y% do NOT simply add up; the net effect is less: Net discount = [x + y − (xy/100)]%.

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Algebra — Mathematics · 8 cards

Variable and constant: A variable (x, y, z) represents an unknown quantity; a constant is a fixed number. An algebraic expression combines variables and constants using operations.
Linear equation in one variable: An equation of the form ax + b = 0, where a ≠ 0. It has exactly one solution: x = -b/a. The degree (highest power of the variable) is 1.
Simultaneous linear equations: Two equations in two variables (x and y) that must both be true at the same time. Standard form: a₁x + b₁y = c₁ and a₂x + b₂y = c₂. They usually have one unique solution unless the lines are parallel or coincident.
Substitution method: Solve one equation for one variable, then substitute that expression into the other equation. Useful when one equation is already isolated or easy to isolate.
Elimination method: Multiply equations by suitable numbers so that adding or subtracting them cancels one variable. Often faster than substitution when coefficients align nicely.
Algebraic identities: Pre-proved formulas that allow quick expansion or factorisation. The exam tests the three core square identities and their applications to simplify expressions and solve equations.
Transposition: Moving a term from one side of an equation to the other by reversing its operation (addition ↔ subtraction, multiplication ↔ division). Maintain equality by performing the same operation on both sides.
Word-problem translation: Keywords map to operations — "sum" → +, "difference" → −, "product" → ×, "is/equals" → =. Age, money, and number problems can appear disguised as algebra.

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Geometry — Mathematics · 8 cards

Lines and angles: When two lines intersect, vertically opposite angles are equal. When a transversal cuts parallel lines, corresponding angles are equal, alternate interior angles are equal, and co-interior angles sum to 180°.
Triangle angle-sum property: The three interior angles of any triangle always sum to 180°. An exterior angle of a triangle equals the sum of the two non-adjacent interior angles.
Triangle congruence: Two triangles are congruent if they satisfy SSS (three sides equal), SAS (two sides and included angle), ASA (two angles and included side), or RHS (right angle, hypotenuse, one side) criteria.
Pythagoras theorem: In a right-angled triangle, the square of the hypotenuse equals the sum of squares of the other two sides: c² = a² + b². Common Pythagorean triplets: (3,4,5), (5,12,13), (8,15,17), (7,24,25).
Circle angle theorems: The angle subtended by an arc at the center is double the angle subtended at any point on the circle. Angles in the same segment are equal. Angle in a semicircle is 90°.
Tangent properties: A tangent to a circle is perpendicular to the radius at the point of contact. Two tangents drawn from an external point are equal in length.
Triangle inequalities: The sum of any two sides of a triangle must be greater than the third side. The difference of any two sides must be less than the third side.
Special triangles: In an equilateral triangle, all angles are 60° and all sides equal. In an isosceles triangle, angles opposite equal sides are equal. In a 30-60-90 triangle, sides are in ratio 1 : √3 : 2.

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Trigonometry — Mathematics · 11 cards

Trigonometric ratios: are defined for acute angles in a right triangle. For angle θ: sin θ = opposite/hypotenuse, cos θ = adjacent/hypotenuse, tan θ = opposite/adjacent, and the reciprocals cot θ = 1/tan θ, sec θ = 1/cos θ, csc θ = 1/sin θ.
Standard angles: (0°, 30°, 45°, 60°, 90°) have exact ratio values that must be memorized.
Pythagorean identities: connect sin, cos, and tan: sin²θ + cos²θ = 1, 1 + tan²θ = sec²θ, and 1 + cot²θ = csc²θ. These are tools for simplification and substitution.
Complementary angle relations: sin(90° − θ) = cos θ, cos(90° − θ) = sin θ, tan(90° − θ) = cot θ. Use these when the problem mixes angles like 30° and 60°.
Height and distance problems: translate real-world scenarios (towers, ladders, kites) into right triangles. The "angle of elevation" is measured upward from horizontal; "angle of depression" is measured downward from horizontal.
sin θ: 0°: 0 · 30°: 1/2 · 45°: 1/√2 · 60°: √3/2 · 90°: 1
cos θ: 0°: 1 · 30°: √3/2 · 45°: 1/√2 · 60°: 1/2 · 90°: 0
tan θ: 0°: 0 · 30°: 1/√3 · 45°: 1 · 60°: √3 · 90°: undefined
cot θ: 0°: undefined · 30°: √3 · 45°: 1 · 60°: 1/√3 · 90°: 0
sec θ: 0°: 1 · 30°: 2/√3 · 45°: √2 · 60°: 2 · 90°: undefined
csc θ: 0°: undefined · 30°: 2 · 45°: √2 · 60°: 2/√3 · 90°: 1

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Elementary Statistics — Mathematics · 7 cards

Mean (Arithmetic Average): Sum of all observations divided by the number of observations. Represents the "central" or typical value. Sensitive to extreme values (outliers). Formula: Mean = (Sum of all values) / (Number of values).
Median: The middle value when data is arranged in ascending or descending order. For odd number of observations, it's the middle term; for even number, it's the average of the two middle terms. Not affected by extreme values, making it robust for skewed data.
Mode: The observation that appears most frequently in a dataset. A dataset can have no mode (all values appear once), one mode (unimodal) or multiple modes (bimodal, trimodal). Useful for categorical data like most popular shirt size or most common exam score.
Range: Difference between the largest and smallest observations in the dataset. Measures the spread or dispersion. Range = Maximum value − Minimum value. A larger range indicates greater variability.
Data Interpretation: Reading tables, bar graphs, pie charts or line graphs to extract values and perform calculations. Often combined with percentage, ratio or comparison operations. Always check units, scales and legends carefully.
Weighted Mean: When different observations have different "weights" or importance. Formula: Weighted Mean = (Sum of (value × weight)) / (Sum of weights). Common in questions involving marks with different subject weightages.
Grouped Data Mean: When data is given in class intervals with frequencies. Use the midpoint (class mark) of each interval: Mean = (Sum of (frequency × midpoint)) / (Total frequency).

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Calendar and Clock — Mathematics · 8 cards

Odd days: are the extra days beyond complete weeks when calculating total days. One week = 0 odd days; 8 days = 1 odd day; 9 days = 2 odd days, and so on. To find the day of the week, calculate total odd days and apply modulo 7.
Ordinary year: has 365 days = 52 weeks + 1 day = 1 odd day. Leap year has 366 days = 52 weeks + 2 days = 2 odd days. A year is a leap year if divisible by 4, except century years (1800, 1900) which must be divisible by 400 (so 2000 was a leap year, but 1900 was not).
Counting centuries: Every 100 years gives 76 ordinary years (1 odd day each = 76) + 24 leap years (2 odd days each = 48) = 124 odd days = 17 weeks + 5 odd days. So 100 years = 5 odd days; 200 years = 3 odd days; 300 years = 1 odd day; 400 years = 0 odd days.
Month odd days (non-leap year): Jan=3, Feb=0, Mar=3, Apr=2, May=3, Jun=2, Jul=3, Aug=3, Sep=2, Oct=3, Nov=2, Dec=3. For leap years, add 1 to February (Feb=1) and adjust accordingly for dates after February.
Clock angle formula: The angle between hour and minute hands at time H hours and M minutes is |30H - 6M + M/2| or |11M/2 - 30H|. Use the absolute value and if the result exceeds 180°, subtract from 360° to get the smaller angle.
Hands coincide: when both hands overlap—this happens 11 times in 12 hours (not 12, because at 11 o'clock the next coincidence is at 12). They meet every 65 and 5/11 minutes.
Hands at right angles: (90° or 270°) occurs 22 times in 12 hours. Hands are opposite (180°) 11 times in 12 hours.
Relative speed: Minute hand moves 6° per minute; hour hand moves 0.5° per minute. The minute hand gains 5.5° per minute over the hour hand (6 - 0.5 = 5.5).

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Pipes and Cisterns — Mathematics · 8 cards

Rate of work analogy: If a pipe fills a tank in n hours, its rate is 1/n tank per hour. If it empties in m hours, its rate is –1/m tank per hour.
Net rate for combined pipes: Add individual rates algebraically. Inlet rates are positive, outlet (leak/drain) rates are negative. Net rate = (sum of inlet rates) – (sum of outlet rates).
LCM method for assumed capacity: When pipes fill in a, b, c hours, assume tank capacity = LCM(a, b, c) litres. Then each pipe's efficiency is capacity/time in litres per hour. This avoids fractions in intermediate steps.
Time to fill/empty together: If net rate is R tank/hour, time = 1/R hours. If net rate is negative, the tank empties; if positive, it fills.
Partial work in cycles: When pipes operate alternately (e.g. A for 1 hour, B for 1 hour, repeat), calculate work done in one complete cycle, then see how many cycles are needed.
Pipe opened/closed mid-way: Compute work done in each phase separately. Track remaining capacity after each phase and apply the next pipe's rate to that remainder.
Leak or waste pipe: Treat as an outlet. If a leak empties the full tank in L hours, its rate is –1/L.
Multiple inlets and outlets: Sum all inlet rates, sum all outlet rates, then subtract. The sign of the result tells you if the tank is filling or emptying.

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Analogies — General Intelligence and Reasoning · 8 cards

Relationship identification is primary: Every analogy is built on one specific relationship between the first pair. Your first task is always to articulate this relationship clearly before looking at options.
Same relationship, different content: The second pair must have the identical relationship type but with different elements. For example, if the first pair shows "tool to worker," the second must also show "tool to worker," not "worker to workplace."
Word analogies use semantic and categorical logic: Common relationships include synonyms/antonyms, part-to-whole, category-to-member, cause-and-effect, tool-and-function, and person-to-profession.
Number analogies follow mathematical patterns: Look for arithmetic operations (addition, subtraction, multiplication, division), square/cube relationships, prime numbers, digit sums, or positional patterns.
Figural analogies test visual logic: Elements rotate, reflect, get added or subtracted, change in size/position, or follow completion patterns. Count elements, note shading, and track transformations systematically.
Order matters in pair relationships: "Doctor : Hospital" is directional—it means doctor works at hospital. This is different from "Hospital : Doctor." Always maintain the direction of relationship.
Eliminate by testing each option: When multiple options seem plausible, test each against your identified relationship. The correct answer will satisfy the relationship completely without exceptions.
Watch for distractor options: Wrong answers often share superficial similarity with correct answers but violate the precise relationship. For example, if the relationship is "young-to-mature stage," an option showing "different species of same genus" is a distractor.

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Alphabetical and Number Series — General Intelligence and Reasoning · 8 cards

Number Series Patterns: Most number series use arithmetic operations (add/subtract a constant or increasing difference), geometric operations (multiply/divide by a constant), or special sequences (squares, cubes, primes, Fibonacci). The difference between consecutive terms often reveals the pattern.
Alphabetical Series Logic: Letters are treated by their position (A=1, B=2...Z=26). Patterns include moving forward/backward by a fixed count, skipping letters, or vowel-consonant alternation. Always mentally map the letter to its numeric position to spot the rule.
Mixed Alphanumeric Series: These combine letters and numbers in alternating or grouped fashion. Solve each component separately—the number sequence follows one rule, the letter sequence follows another. Then merge your findings for the complete answer.
Alternating Sequences: Two or more independent sub-series interwoven. For example, positions 1,3,5 follow one pattern while 2,4,6 follow another. Separate odd and even positions, identify each pattern, then determine which sub-series contains the missing term.
Difference of Differences: When first differences don't show a clear pattern, calculate second differences (differences between the differences). A constant second difference indicates a quadratic-type pattern common in competitive exams.
Prime and Special Numbers: Familiarity with primes (2,3,5,7,11,13,17,19,23,29...), perfect squares (1,4,9,16,25,36...), and cubes (1,8,27,64,125...) lets you instantly recognize series built on these sequences.
Positional Alphabet Coding: Some series use EJOTY method (every 5th letter) or similar skip patterns. Knowing that E=5, J=10, O=15, T=20, Y=25 helps spot these quickly.
Reverse Series: Occasionally the series decreases instead of increases. Check if subtracting a constant or dividing produces the pattern. Don't assume all series move forward.

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Coding and Decoding — General Intelligence and Reasoning · 7 cards

Letter shift coding: Each letter moves forward or backward by a fixed number of positions in the alphabet. Example: if the shift is +3, then A→D, B→E, etc. The most common shifts are ±1, ±2, ±3 and the "opposite letter" (A↔Z, B↔Y).
Reverse alphabet substitution: Replace each letter with its counterpart from the opposite end: A↔Z, B↔Y, C↔X and so on. The formula is: position of new letter = 27 – position of old letter.
Position-value coding: Replace each letter with its numerical position in the alphabet (A=1, B=2…Z=26) or apply arithmetic to that position (multiply by 2, add 5, etc.).
Word-based coding: The code changes depending on properties of the entire word—number of letters, vowel count, or position in a given list. For example, words with even letters get one rule, odd letters get another.
Mixed operations: Some codes combine letter shift with reversal, or apply different shifts to alternate letters. These require step-by-step unwrapping.
Analogy format: Given "WORD : CODE", find the code for a second word using the same rule. You deduce the pattern by comparing corresponding letters in the example pair.
Decoding questions: You're given a coded word and must find the original word by reversing the coding rule. These often appear harder but use the exact same patterns in reverse.

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Mathematical Operations — General Intelligence and Reasoning · 7 cards

Symbol Substitution: Standard operators (+, −, ×, ÷) are replaced by arbitrary symbols (★, #, @, etc.) or swapped with each other. You must decode the rule and rewrite the expression in standard form before solving.
Operator Interchange: Two or more operators trade places throughout an equation. For example, if + means × and × means +, then "3 + 4 × 2" becomes "3 × 4 + 2" = 14 in the coded system.
BODMAS Compliance: After substituting symbols, always apply Brackets, Orders, Division/Multiplication (left to right), Addition/Subtraction (left to right). Many traps involve ignoring operator precedence.
Equation Balancing: Some questions ask which symbol makes an equation true. Test each option by substitution and calculation—don't guess based on "looks right."
Mixed Coding: Occasionally symbols represent modified operations, like @ means "add then double" or # means "multiply by the next number's square." Read the rule carefully and apply exactly as stated.
Negative Results and Fractions: Coded operations may yield negative numbers or fractions. Don't assume the answer must be a positive integer—calculate fully.
Direction-Specific Rules: In advanced variants, the operation might depend on position (first occurrence of + means ×, second means +). Track each symbol's context.

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Relationships — General Intelligence and Reasoning · 8 cards

Generation levels: Organize individuals into horizontal tiers — grandparents at top, parents in middle, children at bottom, grandchildren below that. This prevents confusion when multiple generations are involved.
Gender determination: Many problems deliberately omit or obscure gender. Use clues like "sister," "mother," "he," "she" to fix gender; when uncertain, use neutral symbols and derive gender from relationships.
Immediate vs extended family: Immediate family includes parents, siblings, spouse and children. Extended family adds grandparents, aunts, uncles, cousins, in-laws. Know the exact terms: maternal uncle (mother's brother), paternal aunt (father's sister), etc.
Marriage links: When two families connect through marriage, draw a horizontal line (=) between spouses. Their children branch downward from that line. This helps track in-law relationships.
"Only" keywords: "Only son" means no other male siblings; "only child" means no siblings at all. These clues constrain the tree and often unlock the solution.
Self-reference elimination: If the question asks "How is X related to Y?" and your tree shows X = Y (same person), the answer is typically "self" or the question is invalid. Always double-check distinct identities.
Symmetry in relationships: If A is B's uncle, B is A's nephew or niece. Use reverse relationships to verify your tree.
Spouse inference: Statements like "A's father-in-law" imply A is married; the father-in-law is A's spouse's father. Track marriages carefully to avoid mixing bloodlines.

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Syllogism — General Intelligence and Reasoning · 8 cards

Quantifiers: The words "All," "Some" and "No" define the relationship between two categories. "All A are B" means every member of A is also in B. "Some A are B" means at least one A is B (possibly more, possibly all). "No A are B" means A and B have zero overlap.
Subject and Predicate: In "All cats are animals," "cats" is the subject and "animals" is the predicate. The logical rules depend on whether terms are distributed (cover the entire category) or undistributed. "All" distributes the subject; "No" distributes both; "Some" distributes neither.
Venn Diagram Method: Draw overlapping circles for each category. Shade or mark regions according to the statements, then check if the conclusion's diagram must be true based on your sketch. This visual method is foolproof for two-statement problems.
Complementary Pairs: Two conclusions can form a complementary pair if exactly one must be true when neither can be proven individually. The standard pairs are: (1) "Some A are B" and "No A are B," and (2) "Some A are not B" and "All A are B." If statements allow both possibilities, mark "Either I or II follows."
Possibility vs. Definiteness: A conclusion follows only if it is definitely true in every scenario allowed by the statements. If a conclusion is possible but not certain, it does not follow. For example, from "All A are B" and "All B are C," you can conclude "All A are C" (definite), but you cannot conclude "All C are A" (possible but not …
Chain Rule: When three terms link in a chain (A→B, B→C), you can often derive a conclusion about A and C. The middle term (B) must be distributed at least once for a valid chain. For instance, "All A are B" + "All B are C" gives "All A are C," but "All A are B" + "Some B are C" does not guarantee any definite A–C conclusion.
Conversion Rules: "Some A are B" converts to "Some B are A" (always valid). "No A are B" converts to "No B are A" (always valid). "All A are B" does not convert to "All B are A." Use conversions to test conclusions phrased in reverse order.
Ignore Real-World Truth: If the statement says "All pens are chairs," accept it for the logic exercise even though it's factually absurd. Your reasoning must be based solely on the given statements, not on what you know about pens and chairs.

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Jumbling — General Intelligence and Reasoning · 8 cards

Letter Jumbling: Scrambled letters must be rearranged to form a meaningful English word. Focus on common prefixes (un-, pre-, re-), suffixes (-tion, -ing, -ness), and letter patterns (consonant-vowel combinations).
Sentence Jumbling: Four to six sentence fragments (labeled P, Q, R, S or 1, 2, 3, 4) must be arranged to form a coherent paragraph. The first and last sentences are sometimes fixed, narrowing your options.
Mandatory Pairs: Certain words or phrases naturally follow one another (e.g., "not only" must be followed by "but also"; "on the one hand" pairs with "on the other hand"). Identifying these pairs immediately reduces possibilities.
Chronological/Logical Sequence: Events should follow time order or cause-effect relationships. Look for time markers (first, then, finally, meanwhile) and logical connectors (however, therefore, moreover).
Subject-Verb Agreement Clues: The sentence beginning often determines what can follow. A sentence starting with "He" cannot be followed by a fragment starting with "They" unless there's a clear subject change.
Pronoun Reference: Pronouns (he, she, it, they, this, that) must refer to nouns mentioned earlier. A sentence with "This event" cannot come first; something must establish what "this" refers to.
Opening and Closing Indicators: Opening sentences typically introduce a topic broadly; closing sentences conclude, summarize, or provide final thoughts. Sentences with "Thus," "Finally," or "In conclusion" usually come last.
Article Usage: "A" or "An" introduces something new; "The" refers to something already mentioned. A sentence starting with "The dog" likely follows one that introduced "a dog."

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Venn Diagram — General Intelligence and Reasoning · 8 cards

Set: A collection of distinct objects or elements. In Venn diagrams, each set is represented by a circle or closed curve, with the set name typically labeling the circle.
Universal Set: The rectangle enclosing all circles represents the universal set—the complete collection of all elements under consideration. Elements outside all circles but inside the rectangle belong to none of the named sets.
Disjoint Sets: Two or more sets with no common elements are shown as non-overlapping circles (e.g., "Males" and "Females" are disjoint—no person can be both).
Intersection: The overlapping region where two or more sets share common elements. For sets A and B, this region contains elements that are both A AND B (e.g., people who are both "Doctors" and "Women").
Subset Relation: When all elements of one set are contained within another, the smaller circle is drawn completely inside the larger one (e.g., "Roses" is a subset of "Flowers"—all roses are flowers, but not all flowers are roses).
Pairwise Overlap without a Common Region: Three sets where some pairs overlap but not all three share common elements. The diagram shows two-way intersections but no central triple-overlap region.
Complete Overlap: All three (or four) sets share at least some common elements, creating a central region where all sets intersect (e.g., "Students," "Athletes," and "Scholars" might have people who are all three).
Complement: Elements in the universal set but NOT in a particular set are shown in the area outside that set's circle but inside the rectangle.

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Data Interpretation and Sufficiency — General Intelligence and Reasoning · 5 cards

Data Interpretation: means extracting and processing information presented visually or in tabular form to answer specific questions about totals, averages, ratios, percentages or comparisons.
Common data formats: include bar charts (vertical/horizontal bars showing quantities), pie charts (circular sectors showing percentage distribution), line graphs (trends over time), and tables (rows and columns of numerical data).
Data Sufficiency: tests whether the information in one or more statements is adequate to answer the question definitively; you identify the minimum data required without always solving completely.
Read all labels carefully: axis titles, units (thousands, lakhs, percentages), legends explaining bars/lines, and footnotes clarifying data scope; misreading units is a common error source.
Approximation skills: save time—round numbers when the question asks for "approximately" or when answer choices are widely spaced; exact calculation isn't always needed.

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Similarities and Differences — General Intelligence and Reasoning · 8 cards

Odd One Out principle: Three or four items share a common property; one does not. Identify the shared link, then spot the exception.
Similarity matching: Given two groups or pairs, find what quality or category unites them (e.g., all are metals, all are measuring instruments).
Multiple classification bases: Items can be grouped by meaning (synonyms, categories), spelling (number of letters, vowels), numerical properties (even/odd, prime, perfect square), or visual features (shape, symmetry).
Elimination strategy: When unsure, compare each answer choice against the others. The correct odd item will differ in exactly one consistent way from the rest.
Context clues: Words may relate by function (all are tools), origin (all are rivers in India), or usage (all are food items). Numbers may share divisibility, digit patterns, or mathematical properties.
Figures and symbols: For pictorial items, check symmetry, number of sides, shading, rotation, or embedded shapes. The odd figure breaks one visual rule the others follow.
Synonyms vs. antonyms: Sometimes all words except one are synonyms; other times all are related except an antonym or unrelated word.
Practice categories: Familiarize yourself with common groupings—fruits, vegetables, birds, mammals, metals, non-metals, measuring units, geometric terms, Indian states, capitals, currencies, and more.

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Classification — General Intelligence and Reasoning · 7 cards

Homogeneity Principle: Three or four items share a common characteristic (category, property, or pattern), while one item violates this shared property. Your task is to identify the odd one out.
Multiple Classification Bases: Words can be grouped by category (fruits, animals, metals), grammatical form (verbs, nouns), or conceptual relationship (capital cities, scientists). Always choose the most obvious grouping.
Number Properties: Numbers may be classified by mathematical properties such as prime/composite, even/odd, perfect squares/cubes, multiples of a specific number, or arithmetic relationships between digits.
Figure Classification: Visual patterns may involve shape types (polygons, circles), symmetry (axis of symmetry, rotational symmetry), number of elements (sides, angles, enclosed regions), or orientation and shading.
Degree of Oddness: Sometimes multiple items appear different, but one is "most different." Choose the item that violates the most fundamental shared property.
Elimination Strategy: When uncertain, eliminate options systematically. Identify what connects any three items; if one item cannot fit that connection, it's the odd one.
Context Clues: In word classification, consider both literal meanings and abstract relationships. "Rose" might be odd among "Lotus, Water lily, Water hyacinth, Rose" because all the others grow in water, even though all are flowers.

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Directions — General Intelligence and Reasoning · 8 cards

Compass orientation: The standard compass has four cardinal directions—North (top), South (bottom), East (right), West (left)—and four ordinal directions—North-East, South-East, South-West, North-West at 45° angles between cardinals.
Sign convention for displacement: Treat North and East as positive directions, South and West as negative. Net displacement in North-South axis and East-West axis can be calculated algebraically by summing signed distances.
Final position calculation: After all movements, calculate net vertical displacement (North minus South) and net horizontal displacement (East minus West). The shortest distance from start to end is the hypotenuse of the right triangle formed by these two net displacements.
Pythagoras theorem: If net North-South displacement is a units and net East-West displacement is b units, then shortest distance = √(a² + b²).
Direction turning rules: When facing a direction, "left" is 90° counterclockwise, "right" is 90° clockwise. "About turn" is 180°. Practice mental rotation: if facing North, left = West, right = East, about turn = South.
Final direction faced: Track the cumulative turns separately from displacement. Start with initial facing direction, then apply each turn sequentially to find the direction at the end.
Drawing mental or minimal diagrams: In complex problems, sketch a rough cross (N-S-E-W axes), mark movements as arrows with lengths, and track position. This prevents errors in multi-step paths.
45-degree movements: For North-East, South-West etc., resolve displacement into North-South and East-West components. Moving 10 km North-East means moving 10/√2 ≈ 7.07 km North and 7.07 km East (though most exam problems use simpler numbers).

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Cell Biology — General Science · 8 cards

Cell Theory: All living organisms are made of one or more cells; the cell is the basic unit of life; all cells arise from pre-existing cells (Schleiden, Schwann, Virchow).
Prokaryotic vs Eukaryotic: Prokaryotes (bacteria) lack a membrane-bound nucleus and organelles; eukaryotes (plants, animals, fungi) have a defined nucleus and complex organelles.
Cell Membrane: Selectively permeable phospholipid bilayer that controls entry and exit of substances via diffusion, osmosis and active transport.
Nucleus: Control centre containing DNA; regulates gene expression and cell reproduction. Surrounded by a double nuclear membrane with pores.
Cytoplasm: Jelly-like substance filling the cell, where organelles are suspended and many metabolic reactions occur.
Mitochondria: Powerhouse of the cell; performs aerobic respiration to produce ATP (energy currency). Has its own DNA and double membrane.
Chloroplasts: Found only in plant cells and some protists; site of photosynthesis, converting light energy into glucose. Contains chlorophyll pigment.
Cell Division: Mitosis produces two identical daughter cells for growth and repair; meiosis produces four non-identical gametes (sex cells) with half the chromosome number for reproduction.

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Matter and Its States — General Science · 8 cards

Matter definition: Anything that has mass and occupies space. All matter is made of tiny particles (atoms or molecules) in constant motion.
Three common states: Solid (fixed shape and volume), Liquid (fixed volume but takes container's shape), Gas (neither fixed shape nor volume, fills entire container).
Plasma: The fourth state—highly energized gas with free electrons and ions. Found in stars, lightning, and neon signs. Worth knowing.
Particle arrangement: Solids have tightly packed particles in fixed positions; liquids have particles close but mobile; gases have widely separated, freely moving particles.
Interconversion: States change through heating/cooling. Processes: melting (solid→liquid), freezing (liquid→solid), vaporization (liquid→gas), condensation (gas→liquid), sublimation (solid→gas directly), deposition (gas→solid directly).
Physical changes: No new substance forms; only state or appearance changes. Reversible in most cases. Examples: ice melting, sugar dissolving, paper tearing.
Chemical changes: New substance(s) with different properties form. Usually irreversible. Examples: rusting, burning, cooking, digestion.
Energy and state changes: Heating adds kinetic energy to particles, causing state transitions from solid→liquid→gas. Cooling removes energy, reversing the process.

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Physics — General Science · 8 cards

Motion and Force: An object remains at rest or in uniform motion unless acted upon by an external force (Newton's First Law). Force equals mass times acceleration (F = ma). Every action has an equal and opposite reaction.
Energy Conservation: Energy cannot be created or destroyed, only converted from one form to another. Kinetic energy (motion) and potential energy (position) constantly interchange in mechanical systems.
Pressure Fundamentals: Pressure is force per unit area. It increases with depth in liquids. Atmospheric pressure at sea level is approximately 101,325 Pa or 1 atm. Pascal's law states that pressure applied to a confined fluid transmits equally in all directions.
Heat Transfer: Heat flows from hot to cold bodies through conduction (solids), convection (fluids), and radiation (electromagnetic waves). Temperature measures average kinetic energy of particles.
Wave Properties: Sound requires a medium to travel; light does not. Both exhibit reflection and refraction. Sound travels at 343 m/s in air; light travels at 3 × 10⁸ m/s in vacuum.
Electrical Basics: Current (I) is the flow of electric charge. Voltage (V) is electrical potential difference. Resistance (R) opposes current flow. These relate through Ohm's Law: V = IR.
Light Behavior: Light travels in straight lines. Mirrors follow laws of reflection (angle of incidence = angle of reflection). Lenses bend light through refraction, converging or diverging rays.
Magnetism: Every magnet has a north and south pole. Like poles repel; unlike poles attract. A current-carrying conductor produces a magnetic field around it (electromagnetism).

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Units and Measurements — General Science · 6 cards

Physical Quantity: Any measurable property of matter or phenomenon (length, mass, time, temperature). Every physical quantity = numerical value × unit.
Fundamental Quantities: Seven base quantities that cannot be expressed in terms of other quantities: length, mass, time, electric current, temperature, amount of substance, and luminous intensity.
Derived Quantities: All other quantities formed by mathematical combinations of fundamental quantities (area = length², velocity = length/time, force = mass × acceleration).
SI System: International System of Units (Système International), globally accepted since 1960. All scientific and engineering work uses SI for consistency.
Unit Symbol Rules: Always lowercase (m, kg, s) unless named after a person (N for Newton, J for Joule, W for Watt). Never pluralize symbols (5 kg not 5 kgs). Leave space between number and unit (10 m not 10m).
Dimensional Analysis: Checking if both sides of an equation have the same fundamental dimensions (e.g., velocity has dimension LT⁻¹). Useful for verifying formulas and converting units.

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Classification of Organisms — General Science · 5 cards

Taxonomy: is the science of naming, describing and classifying organisms into hierarchical groups. The basic unit is the species; related species form a genus, genera form families, and so on upward through order, class, phylum, and kingdom.
Five-kingdom classification: divides all life into Monera (bacteria), Protista (protozoans and unicellular algae), Fungi (yeasts, molds, mushrooms), Plantae (multicellular plants), and Animalia (multicellular animals). Each kingdom has distinct cellular and nutritional characteristics.
Prokaryotic cells: lack a membrane-bound nucleus and organelles (found only in Monera). Eukaryotic cells have a nucleus and membrane-bound organelles (Protista, Fungi, Plantae, Animalia).
Autotrophs: make their own food through photosynthesis or chemosynthesis (most plants, some bacteria). Heterotrophs obtain food by consuming other organisms (animals, fungi, most protists).
Cell wall composition: varies: bacteria have peptidoglycan, fungi have chitin, plants have cellulose, and animals lack cell walls entirely. This is a key distinguishing feature.

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Atomic Structure — General Science · 8 cards

Atom: The smallest particle of an element that retains chemical identity. Composed of a nucleus (protons + neutrons) and electrons orbiting around it.
Subatomic particles: Protons (positive charge, mass ≈ 1 amu, located in nucleus), neutrons (no charge, mass ≈ 1 amu, in nucleus), electrons (negative charge, negligible mass ≈ 1/1836 amu, orbit nucleus).
Atomic number (Z): Number of protons in the nucleus; defines the element. For a neutral atom, Z also equals the number of electrons.
Mass number (A): Total number of protons and neutrons in the nucleus. A = Z + N (where N is number of neutrons).
Isotopes: Atoms of the same element (same Z) but different mass numbers (different N). Example: Carbon-12, Carbon-13, Carbon-14 all have 6 protons but 6, 7, 8 neutrons respectively.
Isobars: Atoms of different elements with the same mass number but different atomic numbers. Example: Argon-40 (Z=18) and Calcium-40 (Z=20).
Atomic models evolution: Dalton (solid sphere) → Thomson (plum pudding) → Rutherford (nuclear model) → Bohr (electron shells) → Modern quantum mechanical model (electron cloud, orbitals).
Valence electrons: Electrons in the outermost shell determine chemical reactivity and bonding behavior.

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Motion, Force and Laws of Motion — General Science · 8 cards

Motion: is the change in position of an object with respect to time and a reference point. Motion can be uniform (constant speed) or non-uniform (changing speed).
Force: is a push or pull that changes or tends to change the state of rest or motion of an object. It is a vector quantity measured in newtons (N). Multiple forces can act on an object simultaneously; the net or resultant force determines motion.
Inertia: is the tendency of an object to resist changes in its state of motion or rest. Inertia depends solely on mass—greater mass means greater inertia.
Momentum: (p) is the product of an object's mass and velocity: p = mv. It is a vector quantity with SI unit kg·m/s. Momentum represents the "quantity of motion" an object possesses.
Newton's First Law (Law of Inertia): states that an object at rest stays at rest, and an object in motion continues in uniform motion in a straight line, unless acted upon by an external unbalanced force.
Newton's Second Law: quantifies force: The rate of change of momentum is directly proportional to the applied force and occurs in the direction of the force. Mathematically, F = ma (force equals mass times acceleration).
Newton's Third Law (Action-Reaction Law): states that for every action there is an equal and opposite reaction. Forces always occur in pairs acting on two different objects.
Conservation of Momentum: holds that in an isolated system with no external forces, the total momentum before an event equals the total momentum after. This principle governs collisions and explosions.

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Life Sciences (Biology) — General Science · 8 cards

Cell as the unit of life: All living organisms are made of cells. Prokaryotic cells (bacteria) lack a nucleus; eukaryotic cells (animals, plants, fungi) have a membrane-bound nucleus and organelles like mitochondria, ribosomes, endoplasmic reticulum, Golgi apparatus and lysosomes.
Five-kingdom classification: Organisms are grouped into Monera (bacteria), Protista (algae, protozoans), Fungi (yeasts, moulds), Plantae (mosses to flowering plants) and Animalia (sponges to mammals). This classification is based on cell structure, mode of nutrition and body organization.
Photosynthesis and respiration: Green plants synthesize glucose from CO₂ and water using sunlight (photosynthesis: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂). All cells release energy by breaking down glucose in the presence of oxygen (aerobic respiration) or without it (anaerobic respiration/fermentation).
Human organ systems: The body has digestive, circulatory, respiratory, excretory, nervous, endocrine, reproductive, skeletal and muscular systems working in coordination. For example, the heart pumps oxygenated blood via arteries to tissues, and deoxygenated blood returns via veins to the heart, which pumps it to the lungs.
Heredity and DNA: Traits pass from parents to offspring through genes located on chromosomes in the nucleus. DNA (deoxyribonucleic acid) is the hereditary material. Gregor Mendel's experiments with pea plants established the laws of inheritance (dominance, segregation, independent assortment).
Evolution: Species change over time through natural selection (Charles Darwin). Fossils, comparative anatomy and molecular biology provide evidence. Humans (Homo sapiens) evolved from common ancestors shared with other primates over millions of years.
Nutrition and deficiency diseases: Balanced diet includes carbohydrates, proteins, fats, vitamins, minerals, water and roughage. Lack of specific nutrients causes diseases: vitamin A → night blindness, vitamin C → scurvy, vitamin D → rickets, iodine → goiter, iron → anemia.
Ecology and ecosystems: An ecosystem comprises biotic (plants, animals, microbes) and abiotic (air, water, soil) components. Energy flows unidirectionally through food chains (grass → grasshopper → frog → snake → hawk). Nutrients cycle (carbon, nitrogen, water cycles).

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Heredity and Evolution — General Science · 6 cards

Heredity: is the transmission of genetic characteristics from parents to offspring through genes located on chromosomes in the cell nucleus.
Genetics: is the study of heredity and variation; Gregor Mendel is called the "Father of Genetics" for his pioneering pea-plant experiments (1860s).
Dominant alleles: (represented by capital letters, T) mask recessive alleles (lowercase, t) in the phenotype; a recessive trait appears only in homozygous recessive individuals (tt).
Genotype: is the genetic makeup (TT, Tt, tt), while phenotype is the observable trait (tall or short plant).
DNA (deoxyribonucleic acid): is the hereditary material in all living organisms, structured as a double helix with sugar-phosphate backbones and nitrogenous base pairs (A-T, G-C).
Evolution: is the gradual change in species over generations; Darwin's theory of natural selection states that organisms with advantageous traits survive and reproduce more successfully.

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Periodic Classification — General Science · 8 cards

Modern Periodic Law: Elements are arranged in order of increasing atomic number (number of protons). Properties repeat periodically when elements are arranged this way. This corrected Mendeleev's atomic mass-based arrangement.
Periods and Groups: The table has 7 horizontal rows (periods) and 18 vertical columns (groups). Period number = number of electron shells in an atom. Group number often relates to valence electrons (Group 1 = 1 valence electron, Group 17 = 7 valence electrons).
Metals, Non-metals, Metalloids: Metals occupy the left and center (about 78% of elements), non-metals the upper right corner, and metalloids form a diagonal staircase boundary (B, Si, Ge, As, Sb, Te, At).
Valency: The combining capacity of an element. For Groups 1–2, valency equals group number. For Group 13, valency = 3; for Groups 14–17, valency = 18 – group number (e.g., Group 17 has valency 1). Group 18 noble gases have valency 0 (stable, unreactive).
Atomic Size (Radius): Decreases left to right across a period (increasing nuclear charge pulls electrons closer), increases top to bottom down a group (additional electron shells added).
Metallic Character: Increases down a group (easier to lose electrons with more shells) and decreases across a period left to right (non-metallic character increases toward the right).
Reactivity Patterns: For metals, reactivity increases down a group (Group 1: Li < Na < K). For non-metals, reactivity decreases down a group and increases across a period toward Group 17 (halogens are highly reactive).
Noble Gases (Group 18): Helium, Neon, Argon, Krypton, Xenon, Radon — chemically inert with completely filled outermost shells, making them stable and unreactive.

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Gravitation — General Science · 8 cards

Universal Law of Gravitation: Every object in the universe attracts every other object with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres. This is the foundation of planetary motion and satellite dynamics.
Mass vs Weight: Mass is the quantity of matter in an object (measured in kg, constant everywhere). Weight is the gravitational force acting on that mass (measured in N, varies with location). Weight = mass × acceleration due to gravity.
Acceleration due to Gravity (g): On Earth's surface, g ≈ 9.8 m/s² (often approximated as 10 m/s² for quick calculations). This value decreases with altitude and varies slightly with latitude due to Earth's rotation and non-spherical shape.
Free Fall: When an object falls under gravity alone with no air resistance, it is in free fall. All objects in free fall near Earth's surface accelerate at the same rate (g), regardless of their mass—a feather and a hammer fall at the same rate in vacuum.
Variation of g: The value of g decreases as we go above the Earth's surface (on mountains, in aeroplanes) or below the surface (in mines). At the centre of Earth, g = 0.
Gravitational Potential Energy: The energy possessed by an object due to its position in a gravitational field. Near Earth's surface: PE = mgh, where h is height above reference level.
Satellites: Objects that revolve around a planet in a fixed orbit. Artificial satellites stay in orbit because their tangential velocity balances the gravitational pull, creating a continuous free fall around Earth.
Escape Velocity: The minimum velocity needed for an object to break free from a planet's gravitational field without further propulsion. For Earth, escape velocity ≈ 11.2 km/s.

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Zoology — General Science · 8 cards

Animal Kingdom Classification: Animals are grouped by body symmetry, segmentation, coelom (body cavity), notochord presence and level of organization. Major phyla: Porifera (sponges), Coelenterata (jellyfish), Platyhelminthes (flatworms), Aschelminthes (roundworms), Annelida (segmented worms), Arthropoda (insects, crustaceans), Mollusca (snails …
Tissue Types: Four animal tissues — Epithelial (covers surfaces and lines organs), Connective (binds and supports other tissues; includes blood, bone, cartilage), Muscular (contracts to produce movement; skeletal, smooth, cardiac types), Nervous (transmits electrical signals; neurons and support cells).
Blood Components: Blood is liquid connective tissue with plasma (55% liquid portion: water, proteins, nutrients) and formed elements (45%: RBCs carry oxygen, WBCs fight infection, platelets aid clotting). Human blood groups: A, B, AB, O based on antigens; Rh factor (+ or -).
Circulatory System: Heart (four chambers: two atria, two ventricles), arteries (carry oxygenated blood away from heart except pulmonary artery), veins (return deoxygenated blood except pulmonary vein), capillaries (exchange site). Double circulation: pulmonary (heart ↔ lungs) and systemic (heart ↔ body).
Digestive System: Mouth → Esophagus → Stomach → Small intestine (duodenum, jejunum, ileum) → Large intestine → Rectum → Anus. Liver (bile production), Pancreas (enzymes and insulin), enzymes break down carbs/proteins/fats.
Respiratory System: Nose/Mouth → Pharynx → Larynx → Trachea → Bronchi → Bronchioles → Alveoli (gas exchange). Diaphragm muscle aids breathing. Oxygen diffuses into blood, carbon dioxide diffuses out.
Excretory System: Kidneys filter blood to produce urine (removes urea, salts, excess water). Ureters carry urine to bladder; urethra expels it. Nephron is the functional unit of kidney. Skin (sweat), lungs (CO₂, water vapor) also excrete wastes.
Nervous System: Central Nervous System (brain and spinal cord) and Peripheral Nervous System (nerves). Brain: cerebrum (thinking, memory), cerebellum (balance, coordination), medulla (involuntary actions). Neurons transmit impulses via synapse. Reflex arcs provide rapid involuntary responses.

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Chemical Bonding — General Science · 7 cards

Chemical bonds form to achieve stability: . Atoms bond to complete their outermost electron shell, typically achieving eight electrons (octet rule) or two electrons (duet for hydrogen and helium).
Ionic bonding: involves complete transfer of electrons from a metal to a non-metal. The metal loses electrons (becomes a positive cation), the non-metal gains electrons (becomes a negative anion), and electrostatic attraction holds them together.
Covalent bonding: involves sharing of electrons between two non-metals. Both atoms contribute electrons to form shared pairs, allowing each to fill its valence shell without complete transfer.
Metallic bonding: occurs between metal atoms. Valence electrons are delocalized (free to move) in a "sea of electrons" surrounding positive metal ions arranged in a lattice.
Electronegativity: the tendency of an atom to attract shared electrons — determines bond type. Large electronegativity difference (>1.7) favors ionic; small difference favors covalent; zero difference (identical atoms) gives pure covalent.
Bond strength and properties: differ: ionic compounds are hard, brittle, high-melting and conduct when molten/dissolved; covalent compounds are often softer, lower-melting, poor conductors; metals are malleable, ductile, lustrous and good conductors in solid state.
Molecular formulas reflect bonding: NaCl (ionic 1:1), H₂O (covalent sharing), Cu metal (metallic lattice). Recognizing these patterns helps identify bond type instantly.

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Work, Energy and Power — General Science · 8 cards

Work: is done when a force causes displacement in the direction of the force. If there's no displacement or the displacement is perpendicular to the force, work done is zero. Example: carrying a bag horizontally does no work against gravity.
Energy: is the capacity to do work. It exists in multiple forms and is measured in the same unit as work (joules). An object possesses energy if it can exert a force through a distance.
Power: measures the rate of doing work or transferring energy. High power means work is done quickly; low power means the same work takes longer. A 100-watt bulb uses energy faster than a 40-watt bulb.
Kinetic Energy (KE): is the energy of motion. Any moving object—from a speeding train to a falling raindrop—possesses kinetic energy proportional to its mass and the square of its velocity.
Potential Energy (PE): is stored energy due to position or configuration. Gravitational PE depends on height; elastic PE is stored in compressed springs or stretched rubber bands.
Law of Conservation of Energy: states that the total energy in an isolated system remains constant. Energy transforms between forms but the sum never changes. A pendulum continuously converts PE to KE and back.
Energy conversions: occur in every device we use. Batteries convert chemical energy to electrical; motors convert electrical to mechanical; solar panels convert light to electrical; our bodies convert chemical (food) energy to mechanical and heat.
Efficiency: of any machine or process is always less than 100% because some energy is inevitably lost as heat due to friction, air resistance, or other dissipative forces.

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Chemical Reactions and Equations — General Science · 8 cards

Chemical Reaction: A process where reactants transform into products with new properties; represented by a chemical equation with an arrow (→) separating reactants from products.
Law of Conservation of Mass: Matter cannot be created or destroyed in a chemical reaction; total mass of reactants equals total mass of products, which is why equations must be balanced.
Balanced Equation: An equation with equal numbers of each type of atom on both sides; achieved by adjusting coefficients (numbers before formulas), never subscripts (numbers within formulas).
Types of Reactions: Five main categories—combination (A + B → AB), decomposition (AB → A + B), displacement (A + BC → AC + B), double displacement (AB + CD → AD + CB), and redox (electron transfer).
Oxidation: Loss of electrons or gain of oxygen or loss of hydrogen; oxidation state (number) increases during oxidation.
Reduction: Gain of electrons or loss of oxygen or gain of hydrogen; oxidation state decreases during reduction; oxidation and reduction always occur together (hence "redox").
Oxidizing Agent: The substance that gets reduced while causing oxidation of another substance; it accepts electrons.
Reducing Agent: The substance that gets oxidized while causing reduction of another substance; it donates electrons.

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Human Diseases — General Science · 8 cards

Communicable diseases: are caused by pathogens (bacteria, viruses, fungi, protozoa, helminths) and spread via direct contact, air, water, food, vectors (mosquitoes, flies), or contaminated objects.
Non-communicable diseases (NCDs): do not spread from person to person; they arise from genetic factors, lifestyle choices (diet, exercise, smoking), environmental exposures, or aging processes.
Pathogens: invade the body, multiply, and disrupt normal function. The immune system fights back using white blood cells, antibodies, and memory cells for future protection.
Vectors: are living organisms (usually insects) that carry pathogens from one host to another without suffering from the disease themselves (e.g., female Anopheles mosquito transmits malaria).
Prevention methods: include vaccination (active immunity), maintaining hygiene, safe drinking water, vector control (insecticides, bed nets), balanced nutrition, regular exercise, and avoiding tobacco/alcohol.
Deficiency diseases: result from lack of essential nutrients (vitamins, minerals, proteins) and are a subset of non-communicable diseases—malnutrition weakens immunity and increases susceptibility to infections.
Antibiotics: treat bacterial infections but are ineffective against viruses; misuse leads to antibiotic resistance, a growing public health concern.
Lifestyle diseases: like diabetes, hypertension, and heart disease result from poor diet, sedentary habits, stress, and substance abuse; they are preventable through behavior modification.

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Acids, Bases and Salts — General Science · 8 cards

Acids: are substances that taste sour, turn blue litmus red, and release hydrogen ions (H⁺) in aqueous solution. Examples: hydrochloric acid (HCl), sulphuric acid (H₂SO₄), acetic acid (CH₃COOH). Strong acids ionise completely; weak acids ionise partially.
Bases: taste bitter, feel slippery, turn red litmus blue, and release hydroxide ions (OH⁻) in water. Water-soluble bases are called alkalis. Examples: sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)₂). Strong bases dissociate fully; weak bases partially.
Salts: form when an acid reacts with a base in a neutralisation reaction. They are ionic compounds; common salt (NaCl) is the archetypal example. Salts can be neutral, acidic or basic depending on the parent acid and base.
pH scale: measures acidity or basicity on a 0–14 range. pH < 7 is acidic, pH = 7 is neutral, pH > 7 is basic/alkaline. Each unit is a tenfold change in hydrogen ion concentration. Lower pH means higher acidity.
Indicators: change colour in acidic or basic media. Litmus (red in acid, blue in base), phenolphthalein (colourless in acid, pink in base), and methyl orange (red in acid, yellow in base) are standard lab indicators.
Neutralisation: is the reaction between an acid and a base to produce salt and water: Acid + Base → Salt + Water. The reaction is exothermic (releases heat). Example: HCl + NaOH → NaCl + H₂O.
Strength of acids/bases: depends on degree of ionisation, not concentration. Concentrated vinegar is still a weak acid; dilute HCl is still a strong acid.
Water of crystallisation: is water molecules trapped in the crystal structure of a salt. Example: hydrated copper sulphate (CuSO₄·5H₂O) is blue; anhydrous CuSO₄ is white.

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Heat and Thermodynamics — General Science · 8 cards

Heat: is a form of energy that flows from a hotter body to a colder body due to temperature difference; measured in joules (J) or calories (cal). 1 cal = 4.18 J.
Temperature: is the degree of hotness or coldness of a body, indicating the average kinetic energy of its molecules; measured in Celsius (°C), Kelvin (K) or Fahrenheit (°F). Kelvin is the SI unit.
Specific Heat Capacity (c): is the amount of heat required to raise the temperature of 1 kg of a substance by 1°C (or 1 K). Water has the highest specific heat among common liquids (4200 J/kg·K), making it an excellent coolant.
Latent Heat: is the heat absorbed or released during a phase change (solid↔liquid or liquid↔gas) at constant temperature. Latent heat of fusion (melting/freezing) and latent heat of vaporisation (boiling/condensation) are the two main types.
Heat Transfer Modes: Conduction (direct molecular contact in solids), Convection (fluid movement carrying heat) and Radiation (electromagnetic waves, no medium needed). All three can occur simultaneously in real situations.
Thermal Equilibrium: is reached when two bodies in contact attain the same temperature and net heat flow becomes zero. This is the zeroth law of thermodynamics foundation.
Calorimetry: is the science of measuring heat exchange. Heat lost by hot body = Heat gained by cold body (assuming no loss to surroundings). This principle underpins most numerical problems.
Thermodynamic Processes: Isothermal (constant temperature), Isobaric (constant pressure), Isochoric (constant volume) and Adiabatic (no heat exchange).

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Nutrition and Nutrients — General Science · 8 cards

Nutrients: are chemical substances in food that provide energy, promote growth, repair tissues, and regulate body processes. Six main categories: carbohydrates, proteins, fats, vitamins, minerals, and water.
Macronutrients: (carbohydrates, proteins, fats) are needed in large quantities and provide energy measured in calories. Micronutrients (vitamins, minerals) are needed in small amounts but are essential for metabolic functions.
Vitamins: are organic compounds required in trace amounts. Fat-soluble vitamins (A, D, E, K) are stored in body fat; water-soluble vitamins (B-complex, C) are not stored and need regular replenishment.
Minerals: are inorganic elements essential for bone health, fluid balance, nerve transmission, and enzyme function. Important minerals include calcium, phosphorus, sodium and potassium (major minerals) and iron and iodine (trace minerals).
Deficiency diseases: occur when the body lacks a specific nutrient for prolonged periods. Each vitamin and mineral deficiency produces characteristic symptoms.
Balanced diet: contains all six nutrient groups in correct proportions to maintain health: roughly 50–60% carbohydrates, 10–15% proteins, 20–30% fats, plus adequate micronutrients, fiber, and water.
Malnutrition: includes both undernutrition (insufficient nutrients) and overnutrition (excessive nutrients). Protein-energy malnutrition causes kwashiorkor (protein deficiency) and marasmus (total calorie deficiency).
Roughage (dietary fiber): from plant foods aids digestion and prevents constipation, though it provides no nutrients or energy. Water, though not a nutrient, is essential for all metabolic processes and temperature regulation.

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Metals and Non-Metals — General Science · 8 cards

Physical properties of metals: Metals are lustrous (shiny), malleable (can be hammered into sheets), ductile (can be drawn into wires), good conductors of heat and electricity, have high melting and boiling points (except mercury), and produce a ringing sound when struck (sonorous). Most metals are solid at room temperature;
Physical properties of non-metals: Non-metals are generally dull in appearance, brittle (break easily when stressed), non-malleable, non-ductile, poor conductors of heat and electricity (except graphite, a form of carbon), and have relatively lower melting and boiling points.
Chemical properties of metals: Metals lose electrons to form positive ions (cations). They react with oxygen to form metal oxides which are basic in nature. Metals react with water and acids to release hydrogen gas. More reactive metals displace less reactive metals from their salt solutions.
Chemical properties of non-metals: Non-metals gain electrons to form negative ions (anions). They react with oxygen to form non-metal oxides which are acidic or neutral. Non-metals generally do not react with water or dilute acids (except in special cases).
Reactivity series: Metals arranged in decreasing order of reactivity: Potassium > Sodium > Calcium > Magnesium > Aluminum > Zinc > Iron > Lead > Copper > Mercury > Silver > Gold. This series predicts reaction outcomes and extraction difficulty.
Ionic compounds: Formed when metals transfer electrons to non-metals. These compounds have high melting points, conduct electricity in molten or aqueous state, and are usually soluble in water.
Corrosion: The gradual deterioration of metals due to reaction with moisture and atmospheric gases. Rusting of iron (formation of hydrated iron oxide) is the most common example. Prevention methods include painting, galvanization, electroplating, and alloying.
Metallurgy: The science of extracting metals from their ores and refining them for use. The extraction method depends on the metal's reactivity—highly reactive metals require electrolytic reduction, moderately reactive metals use carbon reduction, and less reactive metals need simple heating.

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Sound and Waves — General Science · 7 cards

Sound is a longitudinal mechanical wave: where particles vibrate parallel to wave direction, creating compressions (high pressure) and rarefactions (low pressure). Unlike transverse waves (light, water surface waves), sound particles oscillate back-and-forth along propagation path.
Medium requirement: Sound needs material particles to transfer energy. Speed varies by medium density and elasticity: fastest in solids (~5000 m/s in steel), slower in liquids (~1500 m/s in water), slowest in gases (~343 m/s in air at 20°C). Sound cannot travel through vacuum.
Wave properties: Frequency (Hz) = vibrations per second; wavelength (λ) = distance between consecutive compressions; amplitude = maximum particle displacement determining loudness. These relate as: Speed (v) = Frequency (f) × Wavelength (λ).
Audible range: Human ear detects 20 Hz to 20,000 Hz. Infrasound (<20 Hz) produced by earthquakes, whales; ultrasound (>20,000 Hz) used in SONAR, medical imaging. Dogs hear up to 50,000 Hz, bats up to 100,000 Hz.
Reflection of sound: follows laws identical to light: angle of incidence equals angle of reflection. Produces echoes when reflected sound reaches listener distinctly after direct sound (minimum 0.1 second gap needed, requiring 17 m minimum distance).
Refraction of sound: occurs when passing between media of different densities, bending away from the normal when it enters a medium where it travels faster (e.g. from air into water). Explains why sound travels farther at night (air layers of different temperatures refract sound downward).
Intensity and loudness: Intensity (energy per unit area) measured in W/m²; loudness (subjective perception) measured in decibels (dB). Normal conversation = 60 dB, threshold of pain = 120 dB. Doubling distance quarters intensity (inverse square law).

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Ecology and Natural Resources — General Science · 8 cards

Ecosystem: A functional unit comprising all living organisms (biotic factors) and non-living components (abiotic factors like air, water, soil) in a given area, interacting through energy flow and nutrient cycling. Examples include forests, ponds, deserts.
Producers (Autotrophs): Green plants and some bacteria that synthesize food from sunlight (photosynthesis) or chemicals (chemosynthesis). They form the base of every food chain and convert solar energy into chemical energy.
Consumers (Heterotrophs): Organisms that depend on others for food. Primary consumers (herbivores) eat producers; secondary consumers (carnivores) eat herbivores; tertiary consumers eat secondary consumers. Omnivores consume both plants and animals.
Decomposers: Bacteria and fungi that break down dead organic matter into simpler inorganic substances, returning nutrients to the soil. Without decomposers, nutrients would remain locked in dead bodies and ecosystem productivity would collapse.
Food Chain: Linear sequence showing energy transfer from producers through successive consumer levels. Energy decreases at each step (only ~10% transfers to the next level), limiting chain length to 4–5 steps maximum.
Food Web: Interconnected food chains in an ecosystem. Most organisms occupy multiple positions in different chains, creating a complex web. More stable than single chains because alternative food sources exist if one species declines.
Trophic Levels: Hierarchical positions in a food chain. First trophic level = producers; second = primary consumers; third = secondary consumers, and so on. Energy decreases and number of organisms typically decreases at higher levels (pyramid structure).
Biogeochemical Cycles: Cyclic pathways through which nutrients (carbon, nitrogen, water, oxygen) move between living organisms and the physical environment. These cycles maintain ecosystem balance and ensure continuous nutrient availability.

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Carbon and Its Compounds — General Science · 8 cards

Catenation: Carbon's unique ability to form long, stable chains and rings by bonding with other carbon atoms. This property, combined with tetravalency (four bonds), enables the existence of millions of organic compounds.
Allotropy: The phenomenon where an element exists in two or more different physical forms in the same state. Carbon shows allotropy in the solid state with distinct crystalline structures.
Hydrocarbons: Organic compounds containing only carbon and hydrogen. They serve as the simplest organic molecules and the parent structures for all other organic compounds.
Saturated vs Unsaturated: Saturated hydrocarbons have only single bonds between carbon atoms (alkanes). Unsaturated hydrocarbons contain double (alkenes) or triple (alkynes) bonds, making them more reactive.
Functional Groups: Specific atoms or groups of atoms that replace hydrogen in hydrocarbons and determine the chemical properties of the molecule. The same functional group behaves similarly across different carbon chains.
Homologous Series: A family of organic compounds with the same functional group, similar chemical properties, and each successive member differing by a CH₂ unit with a regular gradation in physical properties.
Nomenclature: Systematic naming uses prefixes (meth-, eth-, prop-, but-) based on the number of carbons, followed by suffixes indicating the type of compound (-ane, -ene, -yne, -ol, -al, -one, -oic acid).
Isomerism: Compounds with the same molecular formula but different structural arrangements. Butane (C₄H₁₀) exists as n-butane and isobutane.

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Light – Reflection and Refraction — General Science · 8 cards

Reflection of Light: Light bounces off surfaces following two laws—(i) incident ray, reflected ray and normal lie in one plane; (ii) angle of incidence equals angle of reflection. Plane mirrors form virtual, erect, laterally inverted images at the same distance behind the mirror.
Spherical Mirrors: Concave mirrors converge light (focus is real, in front); convex mirrors diverge light (focus is virtual, behind). Focal length f = R/2 where R is radius of curvature. Concave mirrors can form real or virtual images depending on object position; convex mirrors always form virtual, diminished, erect images.
Refraction of Light: Light bends when passing from one medium to another due to speed change. If entering a denser medium, it bends toward the normal; entering a rarer medium, it bends away. Refractive index n = speed of light in vacuum / speed in medium.
Lenses: Convex (converging) lenses bring parallel rays to a real focus; concave (diverging) lenses spread rays from a virtual focus. Power of lens P (in dioptre) = 1/f (in metres). Convex lenses form real inverted images when object is beyond focal length, virtual magnified when within;
Prism and Dispersion: White light splits into seven colours (VIBGYOR) when passing through a prism because different wavelengths refract differently (violet bends most, red least). This is dispersion. Rainbows form by dispersion and internal reflection in water droplets.
Human Eye: The eye lens is convex and flexible; ciliary muscles adjust its curvature (accommodation) to focus near or far objects on the retina. The retina contains rods (dim light, black-white vision) and cones (bright light, colour vision).
Defects of Vision: Myopia (short-sightedness)—distant objects blurry, corrected by concave lens. Hypermetropia (long-sightedness)—near objects blurry, corrected by convex lens. Presbyopia—age-related loss of accommodation, corrected by bifocal lenses.
Total Internal Reflection: When light travels from denser to rarer medium at angle greater than critical angle, it reflects completely back into denser medium. Used in optical fibres and sparkling of diamonds.

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Combustion and Fuels — General Science · 8 cards

Combustion: is a chemical process where a substance reacts with oxygen, releasing heat and light. It is an exothermic oxidation reaction. Common examples include burning of wood, coal, petrol, and natural gas.
Three conditions required for combustion: (1) presence of a combustible substance (fuel), (2) presence of a supporter of combustion (oxygen/air), and (3) heating to ignition temperature. Remove any one condition and combustion stops—this principle is used in fire extinguishers.
Ignition temperature: is the minimum temperature at which a substance catches fire and starts burning. Different substances have different ignition temperatures: phosphorus has very low ignition temperature (about 35°C), while coal has high ignition temperature (around 600°C).
Combustible vs non-combustible substances: Combustible substances can burn (wood, paper, petrol, LPG, coal). Non-combustible substances cannot burn (stone, glass, iron, water). Some substances like sodium and phosphorus are highly combustible and can catch fire at room temperature.
Calorific value: is the amount of heat energy produced when 1 kilogram of fuel is completely burnt. It is measured in kilojoules per kilogram (kJ/kg). Higher calorific value means better fuel efficiency—more energy per unit mass.
Ideal fuel characteristics: high calorific value, moderate ignition temperature, burns without smoke or harmful gases, easy to store and transport, economical, leaves minimal residue (ash), and readily available. No single fuel meets all criteria perfectly.
Flame: is the visible gaseous part of fire. Substances that vaporize during burning produce flame (candles, LPG, kerosene). Substances that don't vaporize don't produce flame (coal, charcoal). Flames have different zones with varying temperatures and combustion states.
Clean fuels vs traditional fuels: CNG, LPG, and biogas produce less pollution compared to coal and wood. Government promotes CNG in vehicles and LPG for cooking to reduce air pollution and improve public health.

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Current Electricity — General Science · 6 cards

Electric current: is the rate of flow of electric charge. Measured in amperes (A), where 1 A = 1 coulomb per second. Conventional current flows from positive to negative terminal (opposite to electron flow).
Potential difference (voltage): is the work done per unit charge to move charge between two points. Measured in volts (V). A 12 V battery does 12 joules of work per coulomb of charge.
Resistance: opposes current flow and depends on material, length, cross-sectional area, and temperature. Measured in ohms (Ω). Good conductors (copper, silver) have low resistance; insulators (rubber, glass) have very high resistance.
Ohm's law: states that voltage is directly proportional to current when resistance is constant: V = IR. This is valid only for ohmic conductors (metals at constant temperature), not for LEDs, diodes, or filament lamps.
Electrical power: is the rate at which electrical energy is consumed: P = VI = I²R = V²/R. Measured in watts (W) or kilowatts (kW). A 100 W bulb consumes 100 joules per second.
Household electricity: in India is AC (alternating current) at 220–240 V and 50 Hz. Most homes use a three-wire system: live (red/brown), neutral (black/blue), and earth (green/yellow). The fuse or MCB is always connected in the live wire.

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Magnetism and Magnetic Effects — General Science · 8 cards

Magnetism: Property of materials that attract iron, nickel, cobalt (ferromagnetic materials) and produce a magnetic field around them. Natural magnets are lodestone (magnetite); artificial magnets are made by stroking or electrification.
Magnetic field: Region around a magnet or current-carrying conductor where magnetic force is experienced. Represented by magnetic field lines (also called magnetic lines of force) that originate from North pole and terminate at South pole outside the magnet.
Magnetic poles: Every magnet has two poles — North-seeking (N) and South-seeking (S). Like poles repel, unlike poles attract. Poles cannot be isolated — breaking a magnet creates two new dipoles.
Electromagnet: Temporary magnet created by passing electric current through a coil wound around a soft iron core. Magnetism exists only when current flows; used in electric bells, cranes, relays, and motors.
Electromagnetic induction: Phenomenon discovered by Michael Faraday — a changing magnetic field (or relative motion between coil and magnet) induces electromotive force (EMF) in a conductor. Basis of generators, transformers, and induction coils.
Oersted's discovery: Electric current produces a magnetic field around the conductor. A compass needle deflects near a current-carrying wire, proving the magnetic effect of current.
Fleming's Left-Hand Rule: Used to find the direction of force on a current-carrying conductor in a magnetic field (motor principle). Thumb = force/motion, Forefinger = magnetic field, Middle finger = current direction.
Fleming's Right-Hand Rule: Used to find the direction of induced current in a moving conductor in a magnetic field (generator principle). Thumb = motion, Forefinger = field, Middle finger = induced current.

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Energy Sources — General Science · 8 cards

Conventional energy sources: are those traditionally used for decades — coal, petroleum, natural gas, firewood, and flowing water (hydroelectric). Most are non-renewable except firewood (biomass, renewable if trees are replanted) and hydroelectric power, which is renewable but still classified as conventional due to long-established use.
Non-conventional energy sources: are modern, typically renewable alternatives — solar, wind, tidal, geothermal, biogas, and nuclear. These are emphasized in current government policy due to sustainability and lower pollution.
Renewable vs Non-renewable: Renewable sources regenerate naturally on human timescales (solar, wind, biomass); non-renewable sources deplete with use (coal, petroleum, natural gas, uranium).
Fossil fuels: (coal, petroleum, natural gas) formed from ancient organic matter over millions of years. They release CO₂ when burned, contributing to global warming and air pollution.
Solar energy: converts sunlight into electricity (photovoltaic cells) or heat (solar thermal). It's abundant, clean, but depends on weather and requires large panel areas.
Wind energy: uses turbines to convert wind kinetic energy into electricity. Effective in coastal and hilly regions with consistent wind; no fuel cost but requires significant initial investment.
Nuclear energy: splits uranium atoms (nuclear fission) to release enormous heat that generates steam for turbines. Highly efficient but produces radioactive waste requiring careful disposal.
Biogas: is produced by anaerobic decomposition of organic waste (animal dung, crop residue, kitchen waste). Main component is methane (CH₄); used for cooking and small-scale electricity.

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Scientific Instruments and Inventions — General Science · 8 cards

Measuring instruments: are devices designed to quantify physical quantities like temperature, pressure, distance, time, or electrical properties. Each instrument is purpose-built for one or two specific measurements.
Optical instruments: use lenses, mirrors, or prisms to magnify, focus, or analyze light. Examples include microscopes (magnify small objects), telescopes (view distant objects), and periscopes (see over obstacles).
Meteorological instruments: measure atmospheric conditions—barometer for pressure, hygrometer for humidity, anemometer for wind speed, and rain gauge for precipitation.
Medical instruments: apply physics principles for diagnosis and treatment—stethoscope amplifies body sounds, sphygmomanometer measures blood pressure, ECG records heart electrical activity, X-ray machine images internal body structures.
Electrical measuring instruments: quantify electrical properties—ammeter measures current in amperes, voltmeter measures potential difference in volts, galvanometer detects small currents, and ohmmeter measures resistance.
Navigation and positioning instruments: help determine location and direction—compass shows magnetic north, sextant measures angular distances between celestial objects, and altimeter measures altitude above sea level.
Scientific discoveries: often resulted from improved instrumentation. The telescope enabled astronomy breakthroughs, the microscope revealed cellular biology, and precise clocks made navigation possible.
Major physics inventors: span different eras and specializations—mechanics (Newton, Galileo), electricity (Faraday, Ohm, Ampere), thermodynamics (Celsius, Fahrenheit), and modern physics (Einstein, Curie, Rutherford).

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Science and Technology — General Awareness and Current Affairs · 8 cards

ISRO (Indian Space Research Organisation): India's national space agency responsible for satellite launches, planetary missions, and space exploration. Track recent launch vehicle missions (PSLV, GSLV), satellite deployments (communication, navigation, earth observation), and interplanetary missions.
DRDO (Defence Research and Development Organisation): Develops defense technologies including missiles, radars, combat vehicles, and electronic warfare systems. Key recent developments include missile tests (Agni, Prithvi, BrahMos variants), indigenous aircraft systems, and anti-satellite weapons.
Gaganyaan Mission: India's first crewed orbital spaceflight mission planned by ISRO. Multiple unmanned test flights precede the final human mission. Key milestones include crew module testing and astronaut training.
Digital India Initiatives: Government programs promoting digital infrastructure — Aadhaar, UPI, DigiLocker, e-NAM, BHIM, Startup India.
Renewable Energy Technologies: Solar parks, wind energy projects, green hydrogen mission, electric vehicle policies.
Biotechnology and Health Tech: COVID-19 vaccine developments (Covaxin, Covishield), CRISPR gene editing, telemedicine platforms, and India's pharmaceutical achievements.
Artificial Intelligence and Automation: National AI strategy, AI applications in agriculture (precision farming), smart cities, and digital payment systems. Understanding basic AI terminology helps.
Awards for Scientific Excellence: Shanti Swarup Bhatnagar Prize, Padma awards in science categories — know recent Indian scientists honored for breakthrough work.

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Sports — General Awareness and Current Affairs · 12 cards

Major Multi-Sport Events: Olympics (Summer and Winter held every 4 years, staggered by 2 years), Asian Games, Commonwealth Games, and Youth Olympics are the largest platforms where India competes across 20+ disciplines.
Cricket Trophies: ICC Cricket World Cup (ODI, every 4 years), ICC T20 World Cup (every 2 years), ICC Champions Trophy, Ashes (England vs Australia Test series), Ranji Trophy (India's domestic first-class), IPL (Indian Premier League T20 franchise tournament).
Football Tournaments: FIFA World Cup (every 4 years, men's and women's), UEFA Champions League (club-level Europe), Copa América (South America), Indian Super League (ISL), Durand Cup (Asia's oldest football tournament, instituted 1888).
Tennis Grand Slams: Australian Open, French Open (Roland Garros), Wimbledon, US Open — winning all four in a career is a "Career Grand Slam"; in one calendar year is a "Calendar Grand Slam."
Olympic Sports India Excels In: Hockey (8 Olympic gold medals historically; recent bronze in Tokyo 2020), Badminton (PV Sindhu silver 2016, bronze 2020), Wrestling (multiple medals), Shooting, Boxing, Javelin (Neeraj Chopra gold 2020).
Governing Bodies: BCCI (cricket India), FIFA (football global), ICC (cricket global), IOA (Indian Olympic Association), AIFF (All India Football Federation), BWF (Badminton World Federation).
Trophy Terminology: "Cup" usually knockout format; "Trophy" often round-robin or league; "Championship" can be either. Note sport-specific names like "Ashes" (cricket urn), "Davis Cup" (men's tennis team), "Uber Cup" (women's badminton team).
Current Affairs Angle: Keep a running list of Indian gold medalists, world champions, and major tournament hosts (e.g., if India hosted the Cricket World Cup or Commonwealth Games recently, expect questions on venues and outcomes).
FIFA World Cup: Sport: Football · Frequency/Notes: Every 4 years; Qatar 2022 (Argentina won), next 2026 USA/Canada/Mexico
ICC Cricket World Cup: Sport: Cricket (ODI) · Frequency/Notes: Every 4 years; 2023 held in India (Australia won final vs India)
Olympic Games: Sport: Multi-sport · Frequency/Notes: Summer every 4 years; Paris 2024 most recent; Los Angeles 2028 next
Wimbledon: Sport: Tennis · Frequency/Notes: Annual (June–July); oldest Grand Slam (1877), grass courts

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Culture — General Awareness and Current Affairs · 8 cards

State-festival mapping: Most festivals are region-specific. Pongal (Tamil Nadu), Onam (Kerala), Baisakhi (Punjab), Bihu (Assam), Durga Puja (West Bengal), Ganesh Chaturthi (Maharashtra). National festivals like Diwali and Holi are pan-Indian but still have regional variations.
Eight classical dances: Bharatanatyam (Tamil Nadu), Kathak (North India), Kathakali (Kerala), Kuchipudi (Andhra Pradesh), Odissi (Odisha), Manipuri (Manipur), Mohiniyattam (Kerala), Sattriya (Assam). These are recognized by Sangeet Natak Akademi as classical.
Folk dances by state: Bhangra and Gidda (Punjab), Garba and Dandiya (Gujarat), Lavani (Maharashtra), Bihu (Assam), Ghoomar (Rajasthan), Yakshagana (Karnataka). Folk forms outnumber classical ones.
Musical instruments classification: Tata (string—sitar, veena, sarod), Sushir (wind—flute, shehnai), Avanaddha (percussion—tabla, mridangam, dholak), Ghana (solid percussion—cymbals, ghatam). Knowing instrument-type and famous players (Zakir Hussain–tabla, Hariprasad Chaurasia–flute) adds depth.
Monuments and dynasties: Taj Mahal (Mughal–Shah Jahan), Qutub Minar (Slave dynasty–Qutb-ud-din Aibak), Konark Sun Temple (Eastern Ganga–Narasimhadeva I), Khajuraho (Chandela), Hampi (Vijayanagara), Ajanta (Satavahana and Vakataka periods), Ellora (Kailasa temple: Rashtrakuta; also Chalukya). Link each monument to its builder and period.
UNESCO World Heritage Sites in India: 40+ sites including Taj Mahal, Hampi, Khajuraho, Konark, Ajanta-Ellora, Red Fort, Qutub Minar, and Jantar Mantar. Questions may ask "Which of the following is/are UNESCO sites?"
Religious and harvest festivals: Eid (Islam), Christmas (Christianity), Guru Nanak Jayanti (Sikhism), Mahavir Jayanti (Jainism), Buddha Purnima (Buddhism). Harvest festivals: Pongal, Makar Sankranti, Baisakhi, Onam, Bihu—all linked to agricultural cycles.
Performing arts institutions: Sangeet Natak Akademi (music, dance, drama), Sahitya Akademi (literature), Lalit Kala Akademi (visual arts). Questions may ask which body recognizes classical forms or gives awards.

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Economics — General Awareness and Current Affairs · 8 cards

Banking system: Commercial banks accept deposits and give loans; cooperative banks serve rural/agricultural sectors; payment banks offer limited services without lending. Public sector banks are government-owned; private banks are owned by private entities.
Reserve Bank of India (RBI): India's central bank, established 1935. Functions include issuing currency, regulating banks, managing foreign exchange reserves, controlling inflation through monetary policy, and acting as banker to the government.
Monetary policy tools: Repo rate (rate at which RBI lends to banks), reverse repo rate (rate RBI pays on bank deposits), CRR (Cash Reserve Ratio—percentage of deposits banks must hold with RBI), SLR (Statutory Liquidity Ratio—percentage held in liquid assets).
Union Budget: Annual financial statement presented by Finance Minister (usually February 1). It has two parts: Revenue Budget (government's receipts and expenditure) and Capital Budget (capital receipts and payments). Fiscal deficit is the gap between total expenditure and total revenue excluding borrowings.
Economic indicators: GDP (Gross Domestic Product) measures total economic output; inflation measures price rise (CPI—Consumer Price Index for retail inflation; WPI—Wholesale Price Index for wholesale); fiscal deficit shows government borrowing needs; current account deficit measures trade imbalance.
Government schemes: Flagship programs like PM-KISAN (direct cash to farmers), Ayushman Bharat (health insurance), MGNREGA (rural employment guarantee), PM Awas Yojana (housing), Pradhan Mantri Jan Dhan Yojana (financial inclusion through bank accounts).
GST (Goods and Services Tax): Unified indirect tax launched July 2017, replacing multiple state and central taxes. Four main slabs: 5%, 12%, 18%, 28%. Administered by GST Council chaired by Union Finance Minister.
Taxation: Direct taxes (income tax, corporate tax) paid directly to government; indirect taxes (GST, customs duty) collected via intermediaries. Income tax has progressive slabs; recent budgets often adjust exemption limits and rates.

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Politics — General Awareness and Current Affairs · 8 cards

Union Government: Executive power vests in the President (nominal head), exercised by Prime Minister and Council of Ministers. Parliament (Lok Sabha + Rajya Sabha) makes laws. Supreme Court is the highest judiciary.
State Government: Governor is constitutional head, Chief Minister leads the executive. State Legislature (Vidhan Sabha and in some states Vidhan Parishad) passes state laws. High Court is the top state judiciary.
Parliamentary vs Presidential: India follows the Westminster parliamentary system where the executive is responsible to the legislature, not a fixed-term Presidential system like the USA.
Fundamental Rights and Duties: Articles 12–35 guarantee six fundamental rights (Right to Equality, Freedom, Against Exploitation, Freedom of Religion, Cultural and Educational Rights, Constitutional Remedies). Article 51A lists 11 Fundamental Duties.
Directive Principles of State Policy (DPSP): Articles 36–51 are non-justiciable guidelines for state policy (e.g., uniform civil code, free legal aid, village panchayats).
Amendment Process: Article 368 allows Parliament to amend the Constitution. Some amendments need simple majority, others need special majority (2/3 present + majority of total), and some need ratification by half the states.
Emergency Provisions: Three types — National Emergency (Article 352), President's Rule in states (Article 356), Financial Emergency (Article 360). Each has specific triggers and consequences.
Election Commission of India: Constitutional body (Article 324) conducting free and fair elections. Chief Election Commissioner and Election Commissioners appointed by President, cannot be removed easily, ensuring independence.

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Indian History — General Awareness and Current Affairs · 8 cards

Ancient India foundations: Indus Valley Civilization (3300–1300 BCE) represents India's earliest urban culture; Vedic period (1500–500 BCE) introduced caste system and Vedic literature; Mauryan Empire (321–185 BCE) under Chandragupta and Ashoka unified most of India.
Medieval consolidation and invasions: Delhi Sultanate (1206–1526) marked Islamic rule establishment; Mughal Empire (1526–1857) created architectural marvels and administrative systems; Vijayanagara and Maratha empires represented southern and Deccan resistance.
Colonial transformation: Battle of Plassey (1757) initiated British political control; Revolt of 1857 ended Mughal rule and began direct British governance; Indian National Congress (1885) channelized nationalist aspirations.
Freedom struggle phases: Early Moderates (1885–1905) sought reforms through petitions; Extremists (1905–1919) demanded swaraj; Gandhian era (1920–1947) mobilized masses through non-cooperation, civil disobedience and Quit India movements.
Partition and Independence: Mountbatten Plan (June 1947) accepted India's division; India gained independence on 15 August 1947 while Pakistan was created; Dr. Rajendra Prasad became first President; Jawaharlal Nehru became first Prime Minister.
Cultural continuity: Buddhism and Jainism emerged as reform movements (6th century BCE); Bhakti and Sufi movements promoted devotion over ritual; Indian Renaissance (19th century) combined Western ideas with Indian tradition.
Key battles shaped destiny: Battles of Panipat (1526, 1556, 1761) decided North Indian rulers; Battle of Plassey (1757) gave British Bengal; Battle of Buxar (1764) secured British paramountcy.
Constitutional evolution: Indian Councils Act 1909 and Government of India Acts 1919 and 1935 gradually introduced representative elements; Cabinet Mission Plan (1946) proposed federal structure; Constituent Assembly adopted Constitution on 26 November 1949, effective 26 January 1950.

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Indian and World Geography — General Awareness and Current Affairs · 8 cards

Physical Geography: refers to natural features—mountains, rivers, plateaus, deserts, coastlines—while Political Geography covers man-made divisions like states, districts, capitals and boundaries. Know the distinction; questions may ask "which state has this river" or "capital of this state."
India has six major physiographic divisions: the Himalayas, Northern Plains, Peninsular Plateau, Indian Desert, Coastal Plains, and Islands. Each region has distinct landforms, climate and economic activities. The Himalayas are young fold mountains; the Peninsular Plateau is an ancient stable block.
River systems: are classified by drainage direction. The Himalayan rivers (Ganga, Brahmaputra, Indus) are perennial and snow-fed; Peninsular rivers (Godavari, Krishna, Kaveri, Narmada, Tapi) are seasonal and rain-fed. Know which rivers flow east (into Bay of Bengal) versus west (into Arabian Sea).
Economic Geography: links resources to production. Black soil (regur) suits cotton; alluvial soil suits wheat and rice; red soil suits millets. Iron ore is in Jharkhand-Odisha belt; coal in Jharkhand-Chhattisgarh-West Bengal. Petroleum is in Mumbai High, Assam-Arunachal and Krishna-Godavari basin.
India's neighboring countries: (seven land neighbors): Pakistan, Afghanistan, China, Nepal, Bhutan, Bangladesh, Myanmar. Two sea neighbors: Sri Lanka and Maldives. Questions may ask about borders, passes (Khyber, Nathu La), or capitals of these nations.
Latitudes and Longitudes: India lies between 8°4'N to 37°6'N latitude and 68°7'E to 97°25'E longitude. The Tropic of Cancer (23°30'N) passes through eight Indian states. Standard Meridian is 82°30'E passing through Mirzapur (Uttar Pradesh).
World Geography basics: Seven continents (Asia largest, Australia smallest), five oceans (Pacific largest, Arctic smallest). The Equator divides Earth into Northern and Southern hemispheres; Prime Meridian divides into Eastern and Western hemispheres.
Major Indian ports: Mumbai, Chennai, Kolkata, Visakhapatnam, Kandla, Kochi, Mormugao. Know which coast each port is on and what commodities they handle. Mumbai and Kandla are on the west coast; Chennai and Visakhapatnam on the east coast.

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Awards and Honours — General Awareness and Current Affairs · 8 cards

Civilian Awards Hierarchy: India's civilian honours follow a clear order—Bharat Ratna (highest), followed by Padma Vibhushan, Padma Bhushan, and Padma Shri. Bharat Ratna has no quota and is awarded for exceptional service in any field; maximum 3 can be given per year.
Padma Awards Categories: Padma awards are announced on the eve of Republic Day (25 January) and recognize contributions in art, literature, science, sports, social service, public affairs, and civil service. They can be awarded posthumously, and so can the Bharat Ratna (its statutes were amended in January 1966 to permit posthumous awards).
Nobel Prize Fields: Nobel Prizes are awarded in six categories—Physics, Chemistry, Medicine/Physiology, Literature, Peace, and Economics (added 1969). Indians and persons of Indian origin have won Nobles in multiple categories; knowing recent Indian connections matters.
Gallantry Awards: Param Vir Chakra (highest wartime), Ashok Chakra (highest peacetime), Maha Vir Chakra, and Kirti Chakra recognize military and civilian bravery. Knowing PVC and Ashok Chakra basics helps.
Sports Awards: Rajiv Gandhi Khel Ratna (renamed Major Dhyan Chand Khel Ratna in 2021) is India's highest sporting honour. Arjuna Award, Dronacharya Award (coaches), and Dhyan Chand Award (lifetime achievement) are other key sports honours.
International Awards: Beyond Nobel, know Booker Prize (literature in English), Pulitzer Prize (American journalism/literature), Grammy Awards (music), and Oscar/Academy Awards (films).
Field-Specific Awards: Jnanpith Award (highest literary honour in India), Dadasaheb Phalke Award (cinema), Saraswati Samman (literature), and Kalinga Prize (science popularization) are important category-specific awards.
Recent Trend: Questions may ask about first-time achievements—first woman to win a particular award, youngest recipient, or awards given to organizations/institutions rather than individuals.

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Railway General Awareness — General Awareness and Current Affairs · 8 cards

Zonal Structure: Indian Railways is divided into 18 zones (as of 2024), each headed by a General Manager. Zones are further subdivided into divisions for operational efficiency.
Headquarters Location: Each zone has a specific headquarters city. For example, Northern Railway (NR) is headquartered in New Delhi, while Southern Railway (SR) operates from Chennai.
Production Units: Indian Railways manufactures locomotives, coaches, and wheels through dedicated units like CLW (Chittaranjan), DLW (Varanasi), ICF (Chennai), and RCF (Kapurthala).
Gauge System: India uses three rail gauges — Broad Gauge (1676 mm) is the standard; Meter Gauge (1000 mm) and Narrow Gauge (762 mm/610 mm) are legacy systems mostly converted or heritage lines.
Railway Board: The apex decision-making body, headed by the Chairman & CEO, oversees policy, finance, and operations from New Delhi.
Train Categories: Trains are classified as Rajdhani (capital connectors), Shatabdi (day intercity premium), Duronto (non-stop long distance), Vande Bharat (semi-high-speed indigenous), Garib Rath (budget AC), and others.
Electrification: Indian Railways is aggressively electrifying tracks; as of 2023, over 90% of Broad Gauge routes are electrified, reducing diesel dependency.
Safety and Technology: Recent initiatives include Kavach (indigenous train collision avoidance), interlocking systems, and dedicated freight corridors (DFC) for speed and efficiency.

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