Physics
VIBGYOR for EM Spectrum — Violet, Indigo, Blue, Green, Yellow, Orange, Red gives increasing wavelength order. For frequency reverse it. Mnemonic: "Very Intelligent Boys Generally Have Very Good Marks" (decreasing frequency: Gamma, X-ray, UV, Visible, IR, Microwave, Radio).
Right-Hand Thumb Rule — Thumb = current direction, curled fingers = magnetic field direction around a straight conductor. For coils: curl fingers along current, thumb points to North pole. Essential for magnetic effects questions.
Kirchhoff's Junction Mnemonic — "Current IN = Current OUT" at any junction (KCL). Sum of currents entering equals sum leaving. For loop rule (KVL): "Voltage Rise = Voltage Drop" around any closed loop.
Lens Formula Triangle — Cover what you need to find in 1/f = 1/v - 1/u. Cover 'f' to get f = uv/(v-u). Cover 'v' to find image distance. Sign convention: distances measured from optical center.
MOSFET vs BJT — "BJT needs Current, FET needs Voltage" for control. BJT = current-controlled, bipolar (both carriers). FET = voltage-controlled, unipolar (one carrier type dominates).
Escape Velocity Memory — v = √(2gR) where g=gravity, R=radius. Mnemonic: "2 Good Reasons" for square root of 2gR. Independent of projectile mass; only depends on planet's mass and radius.
SHM Time Period Shortcuts — Simple pendulum: T = 2π√(L/g). Spring: T = 2π√(m/k). Remember "Light things swing fast" (L or m in numerator under root means longer period when increased).
Photoelectric Effect Key — Einstein equation: KE(max) = hf - φ. Mnemonic: "High Frequency Frees Electrons" (hf). Work function φ is threshold energy. Increasing intensity increases current, NOT electron energy.
Chemistry
Alcohol Oxidation Ladder — Primary alcohol → Aldehyde → Carboxylic acid (strong oxidation). Secondary alcohol → Ketone (stops here). Tertiary alcohol → No oxidation. Mnemonic: "1° climbs two steps, 2° climbs one, 3° stays home."
Aldehyde vs Ketone Test — Aldehydes give positive Tollen's test (silver mirror) and Fehling's test (red precipitate). Ketones don't. Remember: "ALDehydes Are LOving" (AL-positive tests).
Lucas Test Timing — Tertiary alcohols react immediately (cloudiness). Secondary in 5 minutes. Primary don't react at room temperature. Mnemonic: "3-2-1 Blast-off: Tertiary=instant, Secondary=slow, Primary=no-go."
VSEPR Shape Memory — 2 pairs=linear, 3=trigonal planar, 4=tetrahedral, 5=trigonal bipyramidal, 6=octahedral. Lone pairs repel more: NH₃ (3+1)=pyramidal, H₂O (2+2)=bent. "Lone wolves take more space."
Electron Configuration Aufbau — Order: 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d... Mnemonic diagonal rule or "Lazy Professors Don't Study For Degree Graduation" (s,p,d,f blocks). Fill lowest energy first.
Hückel's Rule for Aromaticity — Must have (4n+2)π electrons in planar cyclic conjugated system. Benzene: n=1, so 6π electrons. Remember "4n+2 makes it TRUE aromatic"; 4n electrons = antiaromatic.
Halogen Reactivity Order — F > Cl > Br > I (reactivity decreases down group). For nucleophilicity in polar protic solvents: reverse order I⁻ > Br⁻ > Cl⁻ > F⁻. "Friendly Fluorine reacts Fast, but Iodide Invades best."
Carbocation Stability — 3° > 2° > 1° > methyl. Stability increases with +I effect and hyperconjugation. Mnemonic: "Three Supporters Better Than Two" (more alkyl groups = more stable carbocation).
Biology
Biomolecule Classification — CHON for organic: Carbohydrates, Hydrocarbons, Oils/fats, Nucleic acids. Proteins need CHONS (+ Sulfur). Mnemonic: "CH-OH makes sugars" (carbohydrates have aldehyde/ketone + OH groups).
Heart Chamber Flow — "Right Atrium → Right Ventricle → Lungs → Left Atrium → Left Ventricle → Body." Mnemonic: "RALLY" (RA-RV-Lungs-LA-LV). Deoxygenated blood goes right; oxygenated goes left.
ABO Blood Groups — Type A has anti-B antibodies, B has anti-A, AB has none (universal receiver), O has both anti-A and anti-B (universal donor). "AB = All Beggar (receives all), O = Only Giver."
Mitosis Phases — PMAT: Prophase, Metaphase, Anaphase, Telophase. Mnemonic: "Please Make A Tea" or "Poor Man's Attempt Twice" (mitosis maintains chromosome number—2n to 2n).
DNA vs RNA Quick — DNA: Deoxyribose, Thymine, Double-strand. RNA: Ribose, Uracil, Usually single-strand. "DNA is Twin" (double helix), "RNA is Unique" (usually single, has Uracil).
Mendel's Law Shortcut — Law of Segregation (one trait): 3:1 ratio in F₂. Law of Independent Assortment (two traits): 9:3:3:1 ratio. Mnemonic: "Single gene = 3:1 Simple, Two genes = 9:3:3:1 Tough."
Kidney Nephron Flow — Glomerulus → Bowman's capsule → PCT → Loop of Henle → DCT → Collecting duct. Mnemonic: "Good Boys Prefer Lemon Drop Candy" for the filtration-reabsorption-secretion pathway.
Endocrine Glands FLAT PEG — FSH, LH, ACTH, TSH from anterior Pituitary. Posterior releases ADH and Oxytocin. Mnemonic: "FLAT (anterior) PEG" helps remember anterior pituitary hormones. Posterior = "PAO" (Posterior-ADH-Oxytocin).