General Science — Study Notes for MPESB Group 1/2/3
Overview
General Science covers fundamental concepts from Physics, Chemistry, and Biology that form the backbone of scientific literacy expected from government employees. In MPESB exams, this section typically tests basic principles, everyday applications, and awareness of scientific phenomena rather than complex calculations.
Questions often appear in a straightforward factual format—identifying units, naming inventors, recognizing chemical formulas, or understanding biological processes. Mastering this topic requires memorizing key facts while understanding the "why" behind common phenomena. Since the syllabus is vast, focus on frequently tested concepts: Newton's laws, mirrors and lenses, acids and bases, the periodic table, human body systems, and diseases.
This section rewards students who can connect classroom science to real-world applications—why pressure cookers cook faster, how vaccines work, or what causes acid rain.
Key Concepts
Physics Fundamentals
- Newton's Three Laws: Inertia (1st), F = ma (2nd), Action-Reaction (3rd) — explain all mechanical motion.
- Work, Energy, Power: Work = Force × Distance; Energy is capacity to do work; Power = Work/Time (unit: Watt).
- Light behavior: Reflection (mirrors), Refraction (lenses); convex lens converges light, concave lens diverges it.
- Sound: Needs a medium to travel; speed in air ≈ 343 m/s; ultrasound (>20,000 Hz) used in medical imaging.
- Electricity: Current = Charge/Time; Ohm's Law: V = IR; conductors allow current, insulators resist it.
Chemistry Fundamentals
- Atoms and Molecules: Atom is the smallest unit; molecules are combinations of atoms (H₂O, CO₂).
- pH Scale: 0-14 range; below 7 is acidic, 7 is neutral, above 7 is basic/alkaline.
- Metals vs Non-metals: Metals are lustrous, malleable, good conductors; non-metals are brittle, poor conductors.
- Chemical Reactions: Combination, decomposition, displacement, double displacement, oxidation-reduction.
- Carbon compounds: Organic chemistry basis; hydrocarbons are carbon-hydrogen compounds (methane CH₄).
Biology Fundamentals
- Cell: Basic unit of life; plant cells have cell wall, animal cells do not.
- Photosynthesis: 6CO₂ + 6H₂O + Sunlight → C₆H₁₂O₆ + 6O₂ (occurs in chloroplasts).
- Human body systems: Digestive (breaks food), Circulatory (blood transport), Respiratory (oxygen exchange), Nervous (signal transmission).
- Vitamins and Deficiency: Each vitamin deficiency causes specific disease (covered in Key Facts below).
Formulas / Key Facts
Physics Facts
| Concept | Formula/Fact |
|---|---|
| Speed | Distance / Time |
| Acceleration | Change in velocity / Time |
| Force | Mass × Acceleration (SI unit: Newton) |
| Pressure | Force / Area (SI unit: Pascal) |
| Density | Mass / Volume |
| Kinetic Energy | ½ × mass × velocity² |
| Potential Energy | mass × g × height |
| Ohm's Law | Voltage = Current × Resistance |
| Mirror formula | 1/f = 1/v + 1/u |
Chemistry Facts
- Atomic number = Number of protons
- Mass number = Protons + Neutrons
- Avogadro's number = 6.022 × 10²³
- Water formula: H₂O; freezes at 0°C, boils at 100°C
- Common acids: HCl (hydrochloric), H₂SO₄ (sulphuric), HNO₃ (nitric)
- Common bases: NaOH (caustic soda), Ca(OH)₂ (slaked lime), NH₄OH (ammonia)
- Rusting: Iron + Oxygen + Water → Iron oxide (Fe₂O₃)
- Baking soda: NaHCO₃ (Sodium bicarbonate)
- Washing soda: Na₂CO₃ (Sodium carbonate)
Biology Facts
| Vitamin | Chemical Name | Deficiency Disease |
|---|---|---|
| A | Retinol | Night blindness |
| B₁ | Thiamine | Beriberi |
| B₁₂ | Cyanocobalamin | Anaemia |
| C | Ascorbic acid | Scurvy |
| D | Calciferol | Rickets |
| E | Tocopherol | Sterility |
| K | Phylloquinone | Blood clotting problems |
- Largest organ: Skin
- Largest gland: Liver
- Smallest bone: Stapes (ear)
- Largest bone: Femur (thigh)
- Blood groups: A, B, AB, O (AB is universal recipient; O is universal donor)
- Normal BP: 120/80 mmHg
- RBC lifespan: ~120 days
- DNA full form: Deoxyribonucleic Acid
Worked Examples
Example 1: Physics — Calculating Force A 5 kg object accelerates at 4 m/s². Find the force applied.
Solution:
- Formula: F = m × a
- F = 5 × 4 = 20 Newton
- Answer: 20 N
Example 2: Chemistry — Identifying Reaction Type When zinc is added to copper sulphate solution, zinc sulphate forms. What type of reaction is this?
Solution:
- Zn + CuSO₄ → ZnSO₄ + Cu
- Zinc displaces copper from its compound
- Answer: Displacement reaction (more reactive element displaces less reactive)
Example 3: Biology — Vitamin Deficiency A patient shows bleeding gums and delayed wound healing. Which vitamin deficiency is indicated?
Solution:
- Bleeding gums and poor wound healing are classic symptoms
- This indicates Vitamin C (Ascorbic acid) deficiency
- Answer: Vitamin C; Disease: Scurvy
Common Mistakes
❌ Confusing mass and weight → Mass is constant everywhere (measured in kg); weight depends on gravity (measured in Newton). On the Moon, your mass stays same but weight decreases.
❌ Mixing up acids and bases by taste → Acids taste sour (lemon), bases taste bitter (soap). Students often reverse this. Remember: Sour = Acid, Bitter = Base.
❌ Thinking veins always carry deoxygenated blood → Pulmonary veins carry oxygenated blood from lungs to heart. The exception must be memorized.
❌ Confusing concave and convex mirrors → Concave mirrors converge light (used in torches, headlights); convex mirrors diverge light (used in rear-view mirrors for wider view).
❌ Forgetting that sound cannot travel in vacuum → Unlike light, sound needs a medium. This is why there is no sound in space.
❌ Mixing up Vitamin D and Calcium deficiency → Rickets (children) and Osteomalacia (adults) result from Vitamin D deficiency, not directly from calcium deficiency, though both affect bones.
Quick Reference
- SI unit of force: Newton; Energy: Joule; Power: Watt; Current: Ampere
- pH of pure water: 7 (neutral)
- Photosynthesis equation: CO₂ + H₂O + Light → Glucose + O₂
- Universal blood donor: O negative; Universal recipient: AB positive
- Speed of light: 3 × 10⁸ m/s; Speed of sound in air: ~343 m/s
- Father of Genetics: Gregor Mendel; Theory of Evolution: Charles Darwin