ISC Class 12 Physics Important Topics 2027
Last updated:
Every topic ranked by how often and how recently it was asked in 4 board + 5 official sample papers (2023–2027). Teal tags = board papers, orange tags = official sample papers.
Top 10 most important topics
| # | Topic | Chapter | Asked in | Importance |
|---|---|---|---|---|
| 1 | Microscope for small objects | Ray Optics and Optical Instruments | Board 2024Sample 2023Sample 2025Sample 2026 | ★★★★★ |
| 2 | Fringe width inversely proportional to slit separation | Wave Optics | Sample 2024Sample 2025Sample 2027 | ★★★★★ |
| 3 | Potential due to a point charge | Electrostatics | Board 2023Sample 2026Sample 2027 | ★★★★☆ |
| 4 | Compound microscope ray diagram (image at D) | Ray Optics and Optical Instruments | Sample 2024Sample 2025Sample 2026 | ★★★★☆ |
| 5 | Electric field on axial line of a dipole | Electrostatics | Board 2026Sample 2023Sample 2027 | ★★★★☆ |
| 6 | Proof of Snell's law using Huygens' principle | Wave Optics | Board 2024Board 2025Sample 2023Sample 2024 | ★★★★☆ |
| 7 | Prism formula relating n, A and δm | Ray Optics and Optical Instruments | Board 2025Sample 2023Sample 2027 | ★★★★☆ |
| 8 | Crossed electric and magnetic fields (velocity selector v = E/B) | Magnetic Effects of Current and Magnetism | Sample 2027 | ★★★★☆ |
| 9 | Refraction at a single spherical surface | Ray Optics and Optical Instruments | Board 2023Sample 2024Sample 2027 | ★★★★☆ |
| 10 | Heating power P = I2 R | Current Electricity | Board 2023Sample 2025Sample 2026 | ★★★★☆ |
Chapter-wise important topics
Electrostatics · Electrostatics and Current Electricity
| Potential due to a point charge asked 3× | Board 2023Sample 2026Sample 2027 | ★★★★☆ |
| Electric field on axial line of a dipole asked 3× | Board 2026Sample 2023Sample 2027 | ★★★★☆ |
| Torque on a dipole τ = p × E asked 2× | Sample 2024Sample 2027 | ★★★☆☆ |
| Resultant dipole moment of a molecule (vector addition) asked 2× | Sample 2025Sample 2026 | ★★★☆☆ |
| Field of an infinite charged plane sheet E = σ/2ε0 asked 2× | Board 2025Sample 2027 | ★★★☆☆ |
| Equatorial plane is locus of zero potential of a dipole asked 3× | Board 2024Board 2025Sample 2023 | ★★★☆☆ |
| No neutral point for equal and opposite charges (dipole) asked 1× | Sample 2027 | ★★☆☆☆ |
| Parallel plate capacitance C = ε0 A/d asked 1× | Sample 2027 | ★★☆☆☆ |
| Electric field on equatorial (broadside) line of a dipole asked 2× | Board 2023Sample 2024 | ★★☆☆☆ |
| Gauss's law: net enclosed charge zero gives zero flux asked 1× | Sample 2026 | ★★☆☆☆ |
| Equivalent capacitance of multi-plate arrangements asked 1× | Sample 2026 | ★★☆☆☆ |
| Net force from symmetric charge distribution on a semicircle asked 1× | Sample 2026 | ★★☆☆☆ |
| Capacitance with a partially/fully filling dielectric slab asked 1× | Sample 2025 | ★☆☆☆☆ |
| Field outside a charged spherical shell via Gauss's law asked 1× | Sample 2025 | ★☆☆☆☆ |
| Gauss's theorem statement asked 1× | Sample 2024 | ★☆☆☆☆ |
| SI unit of electric flux asked 1× | Sample 2024 | ★☆☆☆☆ |
| n identical capacitors in series asked 1× | Sample 2024 | ★☆☆☆☆ |
| Surface of a charged conductor is equipotential (zero work) asked 1× | Sample 2024 | ★☆☆☆☆ |
| Zero work along equatorial line (zero potential) asked 1× | Board 2026 | ★☆☆☆☆ |
| Gauss's law: flux depends only on enclosed charge asked 1× | Board 2026 | ★☆☆☆☆ |
| Series vs parallel capacitance of identical capacitors asked 1× | Board 2026 | ★☆☆☆☆ |
| Field near a charged conductor E = σ/ε0 asked 1× | Sample 2023 | ★☆☆☆☆ |
| Series-parallel combination of capacitors to get a target value asked 1× | Sample 2023 | ★☆☆☆☆ |
| Electrostatic potential energy of a system of charges asked 1× | Sample 2023 | ★☆☆☆☆ |
| Capacitance dependence on plate separation and dielectric asked 1× | Board 2025 | ★☆☆☆☆ |
| Axial field is twice equatorial field for a short dipole asked 1× | Board 2025 | ★☆☆☆☆ |
| Field between two oppositely charged parallel sheets E = σ/ε0 asked 1× | Board 2025 | ★☆☆☆☆ |
| Gauss's law: flux depends only on enclosed charge; dipole gives zero net charge asked 1× | Board 2024 | ★☆☆☆☆ |
| Field of infinite line charge E ∝ λ/r asked 1× | Board 2024 | ★☆☆☆☆ |
| Relative permittivity (dielectric constant) asked 1× | Board 2024 | ★☆☆☆☆ |
| Quantisation of charge asked 1× | Board 2024 | ★☆☆☆☆ |
| Equivalent capacitance of capacitors in series asked 1× | Board 2024 | ★☆☆☆☆ |
| Gauss's theorem, flux depends only on enclosed charge asked 1× | Board 2023 | ★☆☆☆☆ |
| Equipotential surface asked 1× | Board 2023 | ★☆☆☆☆ |
| Combination of capacitors (series and parallel) asked 1× | Board 2023 | ★☆☆☆☆ |
Current Electricity · Electrostatics and Current Electricity
| Heating power P = I2 R asked 3× | Board 2023Sample 2025Sample 2026 | ★★★★☆ |
| Resistance from slope of I-V graph; temperature dependence asked 2× | Sample 2025Sample 2026 | ★★★☆☆ |
| Potentiometer circuit for comparing EMFs asked 2× | Board 2026Sample 2027 | ★★★☆☆ |
| Metre bridge: unknown resistance from balance length asked 2× | Sample 2023Sample 2027 | ★★★☆☆ |
| Internal resistance from potentiometer balancing lengths asked 2× | Sample 2024Sample 2025 | ★★★☆☆ |
| Equal current in series vs parallel cell combinations asked 2× | Sample 2024Sample 2025 | ★★★☆☆ |
| Drift velocity proportional to applied field/PD asked 2× | Sample 2024Sample 2025 | ★★★☆☆ |
| Drift velocity dependence on length (field = V/l) asked 2× | Sample 2024Sample 2025 | ★★★☆☆ |
| Balanced Wheatstone bridge (no galvanometer current) asked 2× | Board 2025Sample 2025 | ★★☆☆☆ |
| Kirchhoff's laws applied to a two-loop network asked 2× | Board 2023Sample 2026 | ★★☆☆☆ |
| Ideal voltmeter has infinite and ideal ammeter zero resistance asked 1× | Sample 2027 | ★★☆☆☆ |
| Resistance independent of applied voltage (Ohm's law) asked 1× | Sample 2027 | ★★☆☆☆ |
| Heating power P = V2/R (parallel) vs P = I2 R (series) asked 1× | Sample 2027 | ★★☆☆☆ |
| Equivalent resistance of a series-parallel network; current from a battery of cells asked 1× | Sample 2027 | ★★☆☆☆ |
| Wheatstone bridge balance condition asked 2× | Board 2023Sample 2024 | ★★☆☆☆ |
| Condition for zero terminal voltage across a cell asked 1× | Sample 2026 | ★★☆☆☆ |
| Potentiometer/metre bridge balance principle asked 1× | Sample 2026 | ★★☆☆☆ |
| Balance relation for unknown resistance from balancing length asked 1× | Sample 2026 | ★★☆☆☆ |
| Kirchhoff's junction rule asked 1× | Sample 2025 | ★☆☆☆☆ |
| Kirchhoff's loop rule asked 1× | Sample 2025 | ★☆☆☆☆ |
| Branch currents of bulbs in parallel (P = VI) asked 1× | Sample 2024 | ★☆☆☆☆ |
| Kirchhoff's loop rule in a bridge network asked 1× | Sample 2024 | ★☆☆☆☆ |
| Electrical power P = VI asked 1× | Board 2026 | ★☆☆☆☆ |
| Kirchhoff's junction rule (conservation of charge) asked 1× | Board 2026 | ★☆☆☆☆ |
| Drift speed ∝ current; relaxation time independent of current asked 1× | Board 2026 | ★☆☆☆☆ |
| Wheatstone-type balance condition (equal potential points) asked 1× | Board 2026 | ★☆☆☆☆ |
| Combination of cells: net emf and internal resistance asked 1× | Board 2026 | ★☆☆☆☆ |
| Resistance of bulb R = V2/P asked 1× | Sample 2023 | ★☆☆☆☆ |
| Kirchhoff's junction rule = conservation of charge asked 1× | Sample 2023 | ★☆☆☆☆ |
| Drift velocity asked 1× | Sample 2023 | ★☆☆☆☆ |
| Uses of a potentiometer asked 1× | Sample 2023 | ★☆☆☆☆ |
| Balance at midpoint requires equal gap resistances asked 1× | Sample 2023 | ★☆☆☆☆ |
| Correct placement of ammeter (series) and voltmeter (parallel) asked 1× | Sample 2023 | ★☆☆☆☆ |
| EMF from energy per unit charge asked 1× | Sample 2023 | ★☆☆☆☆ |
| Cells in series vs parallel: net emf and current through load asked 1× | Board 2025 | ★☆☆☆☆ |
| Kirchhoff's junction and loop rules asked 1× | Board 2025 | ★☆☆☆☆ |
| Potentiometer comparison of EMFs asked 1× | Board 2025 | ★☆☆☆☆ |
| Ammeter and voltmeter identification in a circuit asked 1× | Board 2025 | ★☆☆☆☆ |
| emf and internal resistance from V-I graph asked 1× | Board 2025 | ★☆☆☆☆ |
| Resistivity from slope of J-E graph asked 1× | Board 2025 | ★☆☆☆☆ |
| Drift velocity related to current density / conductivity asked 1× | Board 2025 | ★☆☆☆☆ |
| Drift speed proportional to applied potential difference asked 1× | Board 2024 | ★☆☆☆☆ |
| Metre bridge balance unaffected by interchanging cell and galvanometer asked 1× | Board 2024 | ★☆☆☆☆ |
| EMF of identical cells in parallel equals single cell emf asked 1× | Board 2024 | ★☆☆☆☆ |
| In series, bulb with highest resistance (lowest wattage rating) glows brightest asked 1× | Board 2024 | ★☆☆☆☆ |
| Kirchhoff's laws applied to a network with midpoint tapping asked 1× | Board 2024 | ★☆☆☆☆ |
| Potentiometer: potential gradient and emf measurement asked 1× | Board 2024 | ★☆☆☆☆ |
| Microscopic Ohm's law J = σE asked 1× | Board 2023 | ★☆☆☆☆ |
| Number density of free electrons in drift current relation asked 1× | Board 2023 | ★☆☆☆☆ |
| Series-parallel grouping of cells; net emf, internal resistance, current asked 1× | Board 2023 | ★☆☆☆☆ |
Magnetic Effects of Current and Magnetism · Magnetism and Electromagnetic Induction & Alternating Currents
| Crossed electric and magnetic fields (velocity selector v = E/B) asked 2× | Sample 2027 | ★★★★☆ |
| Ampere's law for a long straight wire asked 3× | Board 2023Sample 2024Sample 2026 | ★★★★☆ |
| Galvanometer to ammeter conversion (shunt) asked 3× | Board 2023Sample 2024Sample 2025 | ★★★☆☆ |
| Diamagnetic susceptibility independent of temperature asked 2× | Sample 2025Sample 2026 | ★★★☆☆ |
| Axial field of a circular coil B = μ0 I a2 /2(a2+x2)3/2 asked 2× | Sample 2025Sample 2026 | ★★★☆☆ |
| Perpendicular magnetic force provides centripetal force asked 2× | Sample 2025Sample 2026 | ★★★☆☆ |
| Radius r = mv/qB asked 2× | Sample 2025Sample 2026 | ★★★☆☆ |
| Magnitude of field of a long straight wire asked 2× | Board 2024Sample 2027 | ★★★☆☆ |
| Field at coil centre when a wire is rewound to a new radius asked 2× | Sample 2024Sample 2025 | ★★★☆☆ |
| Ferromagnetic materials (Fe, Ni, Co) asked 1× | Sample 2027 | ★★☆☆☆ |
| Field inside a solenoid is uniform; field on axis of a circular coil is non-uniform asked 1× | Sample 2027 | ★★☆☆☆ |
| Steel for permanent magnets (high retentivity and coercivity) asked 1× | Sample 2027 | ★★☆☆☆ |
| Field at centre of circular coil from Biot-Savart law asked 2× | Board 2024Sample 2023 | ★★☆☆☆ |
| Zero net force from balanced parallel-wire forces asked 1× | Sample 2026 | ★★☆☆☆ |
| Voltage sensitivity of galvanometer (NAB/kR) asked 1× | Sample 2026 | ★★☆☆☆ |
| Parallel currents in same direction attract asked 1× | Sample 2025 | ★☆☆☆☆ |
| Antiparallel currents repel asked 1× | Sample 2025 | ★☆☆☆☆ |
| Effective resistance of ammeter (parallel of G and shunt) asked 1× | Sample 2025 | ★☆☆☆☆ |
| Magnetic field lines cannot intersect asked 1× | Sample 2024 | ★☆☆☆☆ |
| Definition of ampere via force between parallel conductors asked 1× | Sample 2024 | ★☆☆☆☆ |
| No magnetic force when velocity is parallel to field asked 1× | Board 2026 | ★☆☆☆☆ |
| Paramagnetic susceptibility decreases with temperature (Curie law) asked 1× | Board 2026 | ★☆☆☆☆ |
| Biot-Savart law in vector form asked 1× | Board 2026 | ★☆☆☆☆ |
| Ampere's circuital law statement asked 1× | Board 2026 | ★☆☆☆☆ |
| Field at centre of circular coil of n turns asked 1× | Board 2026 | ★☆☆☆☆ |
| Current sensitivity of galvanometer (NAB/k) asked 1× | Board 2026 | ★☆☆☆☆ |
| Radial field via concave pole pieces and soft iron core asked 1× | Board 2026 | ★☆☆☆☆ |
| Force on a conductor due to field of a parallel current-carrying wire asked 1× | Board 2026 | ★☆☆☆☆ |
| Equilibrium of a current-carrying wire between two others asked 1× | Board 2026 | ★☆☆☆☆ |
| Field inside a long solenoid B = μ0 nI asked 1× | Sample 2023 | ★☆☆☆☆ |
| Force per unit length between parallel currents asked 1× | Sample 2023 | ★☆☆☆☆ |
| Radius of circular path r = mv/qB asked 1× | Sample 2023 | ★☆☆☆☆ |
| Classifying materials by relative permeability asked 1× | Board 2025 | ★☆☆☆☆ |
| Force between parallel currents (antiparallel repel) asked 1× | Board 2025 | ★☆☆☆☆ |
| Field at centre of coil B = μ0 NI/2R scaling asked 1× | Board 2025 | ★☆☆☆☆ |
| Galvanometer to voltmeter conversion (series resistance) asked 1× | Board 2025 | ★☆☆☆☆ |
| Net magnetic field due to two parallel current-carrying wires asked 1× | Board 2025 | ★☆☆☆☆ |
| Circular path of a charged particle in a perpendicular magnetic field asked 1× | Board 2025 | ★☆☆☆☆ |
| Cyclotron frequency f = qB/2πm asked 1× | Board 2025 | ★☆☆☆☆ |
| Lorentz magnetic force vector form asked 1× | Board 2024 | ★☆☆☆☆ |
| Torque on current loop; galvanometer deflection asked 1× | Board 2024 | ★☆☆☆☆ |
| Curie temperature (ferromagnetic to paramagnetic transition) asked 1× | Board 2024 | ★☆☆☆☆ |
| Direction of magnetic field around a straight wire (right-hand rule) asked 1× | Board 2024 | ★☆☆☆☆ |
| Force between two parallel current-carrying wires asked 1× | Board 2024 | ★☆☆☆☆ |
| Magnetic field at centre of circular coil asked 1× | Board 2023 | ★☆☆☆☆ |
| Force on a moving charge in the field of a current-carrying wire asked 1× | Board 2023 | ★☆☆☆☆ |
Electromagnetic Induction and Alternating Currents · Magnetism and Electromagnetic Induction & Alternating Currents
| Step-up transformer asked 2× | Sample 2024Sample 2027 | ★★★☆☆ |
| Sharpness of resonance, Q factor and impedance at resonance asked 2× | Sample 2025Sample 2026 | ★★★☆☆ |
| Capacitive current proportional to frequency asked 2× | Sample 2025Sample 2026 | ★★★☆☆ |
| RMS current in a purely resistive AC circuit asked 2× | Board 2026Sample 2027 | ★★★☆☆ |
| Motional EMF asked 3× | Board 2023Board 2026Sample 2024 | ★★★☆☆ |
| Self-induction produces high emf on breaking circuit asked 2× | Sample 2023Sample 2027 | ★★★☆☆ |
| Lenz's law: direction of induced current asked 1× | Sample 2027 | ★★☆☆☆ |
| Capacitive reactance from AC current-time graph asked 1× | Sample 2027 | ★★☆☆☆ |
| Motional emf ε = Blv asked 1× | Sample 2027 | ★★☆☆☆ |
| Average power in a resistive AC circuit asked 1× | Sample 2027 | ★★☆☆☆ |
| AC preferred to DC (can be stepped up/down by transformer) asked 1× | Sample 2027 | ★★☆☆☆ |
| Soft iron core reduces hysteresis loss asked 2× | Board 2024Board 2026 | ★★☆☆☆ |
| Reducing flux leakage in a transformer asked 1× | Sample 2026 | ★★☆☆☆ |
| Coefficient of self-inductance asked 1× | Sample 2026 | ★★☆☆☆ |
| Inductive reactance and inductance from V-I data asked 1× | Sample 2026 | ★★☆☆☆ |
| Inductive reactance is zero for DC asked 1× | Sample 2026 | ★★☆☆☆ |
| Lamination reduces eddy current losses asked 1× | Sample 2025 | ★☆☆☆☆ |
| Induced emf from rate of change of flux over intervals asked 1× | Sample 2025 | ★☆☆☆☆ |
| Induced current vs time from induced emf asked 1× | Sample 2025 | ★☆☆☆☆ |
| Fleming's right hand rule asked 1× | Sample 2024 | ★☆☆☆☆ |
| Induced emf from change in flux (Faraday's law) asked 1× | Sample 2024 | ★☆☆☆☆ |
| Self-inductance scaling with solenoid dimensions and turns asked 1× | Sample 2024 | ★☆☆☆☆ |
| Series LCR: current, inductance and capacitance from voltmeter readings asked 1× | Sample 2024 | ★☆☆☆☆ |
| Resonant frequency depends on product LC asked 1× | Sample 2024 | ★☆☆☆☆ |
| Inductive reactance; find L from dc resistance and ac impedance asked 1× | Board 2026 | ★☆☆☆☆ |
| Power factor and phase difference asked 1× | Board 2026 | ★☆☆☆☆ |
| Self-inductance of a solenoid L = μ0 μr N2 A / l asked 1× | Board 2026 | ★☆☆☆☆ |
| Energy losses in a transformer asked 1× | Sample 2023 | ★☆☆☆☆ |
| Series LCR at resonance: resonant frequency, reactance, impedance, current, phase asked 1× | Sample 2023 | ★☆☆☆☆ |
| Motional emf and induced current in a rod on rails asked 1× | Sample 2023 | ★☆☆☆☆ |
| Maximum motional emf for a rod in SHM asked 1× | Sample 2023 | ★☆☆☆☆ |
| Step-down transformer: secondary current greater (I∝1/N) asked 1× | Board 2025 | ★☆☆☆☆ |
| Motional emf ε = Blv; Lenz's/Fleming's law for direction asked 1× | Board 2025 | ★☆☆☆☆ |
| Self-inductance from induced emf and rate of change of current asked 1× | Board 2025 | ★☆☆☆☆ |
| Series R-X AC circuit from emf and current equations asked 1× | Board 2025 | ★☆☆☆☆ |
| Step-down transformer in a charger asked 1× | Board 2024 | ★☆☆☆☆ |
| Series RL AC circuit: reactance, impedance, current asked 1× | Board 2024 | ★☆☆☆☆ |
| Impedance vs frequency curve, resonance asked 1× | Board 2024 | ★☆☆☆☆ |
| Self-induction; emf and self-inductance asked 1× | Board 2024 | ★☆☆☆☆ |
| RMS to peak value; dc vs ac asked 1× | Board 2024 | ★☆☆☆☆ |
| Electromagnetic induction (reverse of magnetic effect of current) asked 1× | Board 2023 | ★☆☆☆☆ |
| Series LCR circuit: impedance, peak current, phase difference asked 1× | Board 2023 | ★☆☆☆☆ |
| Frequency and RMS value from AC emf equation asked 1× | Board 2023 | ★☆☆☆☆ |
| Transformer turns ratio, secondary voltage and current asked 1× | Board 2023 | ★☆☆☆☆ |
Electromagnetic Waves · Electromagnetic Waves
| Electromagnetic spectrum in order of frequency asked 1× | Sample 2027 | ★★☆☆☆ |
| Microwaves used in radar asked 1× | Sample 2026 | ★★☆☆☆ |
| X-rays used in crystallography asked 1× | Sample 2026 | ★★☆☆☆ |
| X-rays used in medical imaging asked 1× | Sample 2025 | ★☆☆☆☆ |
| Wavelength range of radio waves asked 1× | Sample 2025 | ★☆☆☆☆ |
| Applications of microwaves asked 1× | Sample 2024 | ★☆☆☆☆ |
| Matter waves are not EM waves asked 1× | Sample 2024 | ★☆☆☆☆ |
| X-rays used in security scanning asked 1× | Board 2026 | ★☆☆☆☆ |
| All EM waves have same speed c in vacuum asked 1× | Board 2026 | ★☆☆☆☆ |
| Infrared for viewing through haze/fog asked 1× | Sample 2023 | ★☆☆☆☆ |
| X-rays wavelength ~0.1nm asked 1× | Sample 2023 | ★☆☆☆☆ |
| Microwaves used in satellite communication asked 1× | Board 2025 | ★☆☆☆☆ |
| c = fλ for EM waves asked 1× | Board 2025 | ★☆☆☆☆ |
| Identifying EM radiation by frequency (microwaves) asked 1× | Board 2024 | ★☆☆☆☆ |
| All EM waves travel at speed c in vacuum asked 1× | Board 2024 | ★☆☆☆☆ |
| Mutual orientation of E, B and propagation direction asked 1× | Board 2023 | ★☆☆☆☆ |
| X-rays used for crystal structure asked 1× | Board 2023 | ★☆☆☆☆ |
Ray Optics and Optical Instruments · Optics
| Microscope for small objects asked 4× | Board 2024Sample 2023Sample 2025Sample 2026 | ★★★★★ |
| Compound microscope ray diagram (image at D) asked 3× | Sample 2024Sample 2025Sample 2026 | ★★★★☆ |
| Prism formula relating n, A and δm asked 3× | Board 2025Sample 2023Sample 2027 | ★★★★☆ |
| Refraction at a single spherical surface asked 3× | Board 2023Sample 2024Sample 2027 | ★★★★☆ |
| Mirror focal length independent of medium; f = R/2 asked 2× | Sample 2026Sample 2027 | ★★★★☆ |
| Bifocal composite lens forms multiple images asked 2× | Sample 2026 | ★★★☆☆ |
| Dispersive power of a medium asked 2× | Board 2026Sample 2027 | ★★★☆☆ |
| Focal length of a lens changes when immersed in a medium asked 2× | Board 2025Sample 2027 | ★★★☆☆ |
| Lens maker's formula with f = R asked 2× | Sample 2024Sample 2025 | ★★★☆☆ |
| Thin prism (small refracting angle) asked 2× | Sample 2024Sample 2025 | ★★★☆☆ |
| Combination of cut lens halves asked 2× | Sample 2024Sample 2025 | ★★★☆☆ |
| Astronomical telescope: objective of large focal length, eyepiece of small focal length asked 1× | Sample 2027 | ★★☆☆☆ |
| Focal length of a convex lens by distant object method asked 1× | Sample 2027 | ★★☆☆☆ |
| Frequency of light unchanged on refraction asked 1× | Sample 2027 | ★★☆☆☆ |
| Cutting/covering part of a lens reduces image brightness only asked 1× | Sample 2027 | ★★☆☆☆ |
| Magnifying power of simple microscope M = 1 + D/f asked 1× | Sample 2027 | ★★☆☆☆ |
| Reflecting telescope: mirror objective, lens eyepiece asked 1× | Sample 2027 | ★★☆☆☆ |
| Parabolic mirror collects light from distant objects efficiently asked 1× | Sample 2027 | ★★☆☆☆ |
| Magnifying power / magnification asked 2× | Board 2024Sample 2023 | ★★☆☆☆ |
| Prism both deviates and disperses white light asked 1× | Sample 2026 | ★★☆☆☆ |
| Advantages of reflecting telescope for large apertures asked 1× | Sample 2026 | ★★☆☆☆ |
| No deviation at normal incidence or equal refractive indices asked 1× | Sample 2026 | ★★☆☆☆ |
| Refraction at each surface of a lens (lens maker's derivation) asked 1× | Sample 2026 | ★★☆☆☆ |
| Lens maker's formula from combining surface equations asked 1× | Sample 2026 | ★★☆☆☆ |
| Magnifying power of telescope depends on objective focal length asked 1× | Sample 2025 | ★☆☆☆☆ |
| Critical angle depends on refractive indices of the pair asked 1× | Sample 2025 | ★☆☆☆☆ |
| Convex mirror gives erect, diminished, wide field of view asked 1× | Sample 2025 | ★☆☆☆☆ |
| Focal length of a lens cut into halves asked 1× | Sample 2025 | ★☆☆☆☆ |
| Total internal reflection in optical fibres asked 1× | Sample 2024 | ★☆☆☆☆ |
| Magnifying power of telescope in normal adjustment asked 1× | Sample 2024 | ★☆☆☆☆ |
| Focal length of a lens cut along the principal axis asked 1× | Sample 2024 | ★☆☆☆☆ |
| Lens disappears when surrounding medium has same refractive index asked 1× | Board 2026 | ★☆☆☆☆ |
| Combination of thin lenses in contact; net power asked 1× | Board 2026 | ★☆☆☆☆ |
| Eyepiece has larger focal length than objective in a microscope asked 1× | Board 2026 | ★☆☆☆☆ |
| Effect of cutting a lens on focal length (lens maker's formula) asked 1× | Board 2026 | ★☆☆☆☆ |
| Prism refractive index at minimum deviation (i = e symmetric) asked 1× | Board 2026 | ★☆☆☆☆ |
| Astronomical telescope ray diagram (normal adjustment) asked 1× | Board 2026 | ★☆☆☆☆ |
| Net power/focal length of lenses in contact asked 1× | Sample 2023 | ★☆☆☆☆ |
| Primary rainbow formation (refraction, TIR, dispersion) asked 1× | Sample 2023 | ★☆☆☆☆ |
| Lens maker's formula derivation asked 1× | Sample 2023 | ★☆☆☆☆ |
| Space telescope avoids atmospheric distortion asked 1× | Sample 2023 | ★☆☆☆☆ |
| Magnifying power and length of astronomical telescope (normal adjustment) asked 1× | Sample 2023 | ★☆☆☆☆ |
| Primary vs secondary rainbow asked 1× | Board 2025 | ★☆☆☆☆ |
| Advantage of mirror objective (reflecting telescope) asked 1× | Board 2025 | ★☆☆☆☆ |
| Combination of thin lenses in contact; net power and focal length asked 1× | Board 2025 | ★☆☆☆☆ |
| Object position for simple microscope (image at D) asked 1× | Board 2025 | ★☆☆☆☆ |
| Nature of image in simple microscope (virtual, erect, magnified) asked 1× | Board 2025 | ★☆☆☆☆ |
| Dispersion by prism; violet deviated most asked 1× | Board 2024 | ★☆☆☆☆ |
| Prism with grazing emergence; critical angle and refraction asked 1× | Board 2024 | ★☆☆☆☆ |
| Lens image size varies with object distance asked 1× | Board 2024 | ★☆☆☆☆ |
| Graphical analysis of lens formula asked 1× | Board 2024 | ★☆☆☆☆ |
| Power of a lens P = 1/f asked 1× | Board 2024 | ★☆☆☆☆ |
| Telescope for distant objects asked 1× | Board 2024 | ★☆☆☆☆ |
| Advantages of reflecting telescope asked 1× | Board 2024 | ★☆☆☆☆ |
| Objective lens differences: microscope vs telescope asked 1× | Board 2024 | ★☆☆☆☆ |
| Concave mirror image location (object inside focus) asked 1× | Board 2023 | ★☆☆☆☆ |
| Microscope in normal use (image at D) asked 1× | Board 2023 | ★☆☆☆☆ |
| Rainbow formation (refraction, dispersion, total internal reflection) asked 1× | Board 2023 | ★☆☆☆☆ |
| Prism formula relating A, δm and refractive index asked 1× | Board 2023 | ★☆☆☆☆ |
| Factors affecting focal length of a lens (lens maker's formula) asked 1× | Board 2023 | ★☆☆☆☆ |
| Convex lens acting as diverging lens (denser surrounding medium) asked 1× | Board 2023 | ★☆☆☆☆ |
| Convex lens used in a camera asked 1× | Board 2023 | ★☆☆☆☆ |
| Magnifying power of compound microscope (image at D) asked 1× | Board 2023 | ★☆☆☆☆ |
| Reflecting vs refracting telescope asked 1× | Board 2023 | ★☆☆☆☆ |
Wave Optics · Optics
| Fringe width inversely proportional to slit separation asked 3× | Sample 2024Sample 2025Sample 2027 | ★★★★★ |
| Proof of Snell's law using Huygens' principle asked 4× | Board 2024Board 2025Sample 2023Sample 2024 | ★★★★☆ |
| Proof of law of reflection using Huygens' principle asked 3× | Board 2023Board 2026Sample 2025 | ★★★☆☆ |
| Path difference for constructive interference = nλ asked 2× | Sample 2024Sample 2027 | ★★★☆☆ |
| Fringe width in YDSE asked 2× | Board 2024Sample 2026 | ★★★☆☆ |
| Closing one slit gives single slit diffraction pattern asked 1× | Sample 2027 | ★★☆☆☆ |
| Primary wavefront asked 1× | Sample 2026 | ★★☆☆☆ |
| Secondary wavefront asked 1× | Sample 2026 | ★★☆☆☆ |
| Wave normal (ray direction) asked 1× | Sample 2026 | ★★☆☆☆ |
| Diffraction of wavefronts through a narrow aperture asked 1× | Sample 2025 | ★☆☆☆☆ |
| Fringe width proportional to screen distance asked 1× | Sample 2025 | ★☆☆☆☆ |
| Fringe width proportional to wavelength asked 1× | Sample 2025 | ★☆☆☆☆ |
| Features of single slit diffraction pattern asked 1× | Sample 2024 | ★☆☆☆☆ |
| Plane wavefront from a distant source asked 1× | Sample 2024 | ★☆☆☆☆ |
| Brightness/intensity of fringes vs source asked 1× | Sample 2024 | ★☆☆☆☆ |
| Fringe spacing is uniform in YDSE asked 1× | Sample 2024 | ★☆☆☆☆ |
| Fringe position proportional to wavelength asked 1× | Board 2026 | ★☆☆☆☆ |
| Interference (double slit) vs diffraction pattern identification asked 1× | Board 2026 | ★☆☆☆☆ |
| White light gives coloured fringes with central white maximum asked 1× | Board 2026 | ★☆☆☆☆ |
| Interference/diffraction establishes wave nature of light asked 1× | Board 2026 | ★☆☆☆☆ |
| Cylindrical wavefront from a line source asked 1× | Sample 2023 | ★☆☆☆☆ |
| Coherent sources asked 1× | Sample 2023 | ★☆☆☆☆ |
| Path difference for nth bright fringe = nλ asked 1× | Sample 2023 | ★☆☆☆☆ |
| Angular width of central maximum = 2λ/a asked 1× | Sample 2023 | ★☆☆☆☆ |
| Angular width increases with wavelength asked 1× | Sample 2023 | ★☆☆☆☆ |
| Condition for observable diffraction (obstacle ~ wavelength) asked 1× | Board 2025 | ★☆☆☆☆ |
| Wavefront diagram for refraction asked 1× | Board 2025 | ★☆☆☆☆ |
| YDSE fringe positions and separation asked 1× | Board 2025 | ★☆☆☆☆ |
| Fringe width varies with wavelength asked 1× | Board 2025 | ★☆☆☆☆ |
| Spherical wavefront from a point source asked 1× | Board 2024 | ★☆☆☆☆ |
| Single slit diffraction intensity distribution asked 1× | Board 2024 | ★☆☆☆☆ |
| Wavefront shape from a distant source asked 1× | Board 2023 | ★☆☆☆☆ |
| Angular width of central maximum vs slit width asked 1× | Board 2023 | ★☆☆☆☆ |
| Condition for sustained interference (coherent sources) asked 1× | Board 2023 | ★☆☆☆☆ |
| YDSE fringe position, find slit separation asked 1× | Board 2023 | ★☆☆☆☆ |
Dual Nature of Radiation and Matter · Dual Nature of Radiation and Matter
| Pair annihilation producing gamma photons asked 2× | Sample 2025Sample 2026 | ★★★☆☆ |
| Photoemission condition: photon energy vs work function asked 2× | Board 2026Sample 2027 | ★★★☆☆ |
| Threshold energy for pair production (mass-energy equivalence) asked 2× | Board 2026Sample 2027 | ★★★☆☆ |
| de Broglie wavelength in terms of kinetic energy asked 2× | Board 2024Sample 2027 | ★★★☆☆ |
| Einstein photoelectric equation, max KE asked 2× | Board 2023Sample 2027 | ★★★☆☆ |
| Stopping potential independent of intensity asked 2× | Board 2024Sample 2025 | ★★☆☆☆ |
| Stopping potential vs frequency graph asked 2× | Board 2025Sample 2023 | ★★☆☆☆ |
| Planck's constant from slope of Vs-f graph asked 2× | Board 2025Sample 2023 | ★★☆☆☆ |
| Scientists and their contributions to modern physics asked 1× | Sample 2027 | ★★☆☆☆ |
| Photon-electron collision: photon gives up all or none of its energy asked 1× | Sample 2027 | ★★☆☆☆ |
| Stopping potential increases with frequency of incident light asked 1× | Sample 2027 | ★★☆☆☆ |
| Electron λ ∝ 1/√E, photon λ ∝ 1/E asked 1× | Sample 2026 | ★★☆☆☆ |
| de Broglie wavelength depends on mass (λ ∝ 1/√m) asked 1× | Sample 2026 | ★★☆☆☆ |
| Einstein's equation: KEmax = hf − W0 asked 1× | Sample 2026 | ★★☆☆☆ |
| Photon energy from Bohr transition; stopping potential asked 1× | Sample 2026 | ★★☆☆☆ |
| de Broglie wavelength equals orbit circumference (Bohr condition) asked 1× | Sample 2025 | ★☆☆☆☆ |
| Dual (wave-particle) nature of matter asked 1× | Sample 2025 | ★☆☆☆☆ |
| Stopping potential decreases with frequency asked 1× | Sample 2025 | ★☆☆☆☆ |
| Work function and slope (h/e) from stopping potential vs frequency graph asked 1× | Sample 2025 | ★☆☆☆☆ |
| de Broglie wavelength λ = h/p asked 1× | Sample 2024 | ★☆☆☆☆ |
| Pair annihilation (matter to energy) asked 1× | Sample 2024 | ★☆☆☆☆ |
| Pair production (energy to matter) asked 1× | Sample 2024 | ★☆☆☆☆ |
| Photoemission depends on frequency exceeding threshold asked 1× | Sample 2024 | ★☆☆☆☆ |
| Photoelectric effect shows particle nature of light asked 1× | Sample 2024 | ★☆☆☆☆ |
| de Broglie wavelength largest for smallest mass through same PD asked 1× | Board 2026 | ★☆☆☆☆ |
| Momentum of a photon p = E/c asked 1× | Board 2026 | ★☆☆☆☆ |
| Max KE depends on work function/threshold frequency asked 1× | Board 2026 | ★☆☆☆☆ |
| Davisson-Germer experiment confirms wave nature of electrons asked 1× | Board 2026 | ★☆☆☆☆ |
| de Broglie wavelength λ ∝ 1/v asked 1× | Sample 2023 | ★☆☆☆☆ |
| de Broglie wavelength ∝ 1/√E asked 1× | Board 2025 | ★☆☆☆☆ |
| Electron diffraction / Davisson-Germer (matter waves) asked 1× | Board 2025 | ★☆☆☆☆ |
| Threshold energy for pair production (1.02 MeV) asked 1× | Board 2025 | ★☆☆☆☆ |
| Threshold frequency asked 1× | Board 2025 | ★☆☆☆☆ |
| Work function asked 1× | Board 2025 | ★☆☆☆☆ |
| Pair production (photon to particle-antiparticle) asked 1× | Board 2024 | ★☆☆☆☆ |
| Threshold frequency and max KE depend on work function asked 1× | Board 2024 | ★☆☆☆☆ |
| de Broglie matter waves asked 1× | Board 2023 | ★☆☆☆☆ |
| Photon energy E = hc/λ asked 1× | Board 2023 | ★☆☆☆☆ |
Atoms and Nuclei · Atoms and Nuclei
| Energy equivalent of 1u (931.5 MeV) asked 2× | Sample 2025Sample 2027 | ★★★☆☆ |
| Isotones (same neutron number) asked 2× | Sample 2024Sample 2027 | ★★★☆☆ |
| Hydrogen spectral series (Lyman UV, Balmer visible) asked 2× | Board 2023Sample 2027 | ★★★☆☆ |
| Velocity of electron in nth Bohr orbit asked 2× | Board 2023Sample 2027 | ★★★☆☆ |
| Energy released in fission from mass defect asked 2× | Sample 2024Sample 2025 | ★★★☆☆ |
| Bohr orbit radius rn ∝ n2 asked 2× | Board 2025Board 2026 | ★★☆☆☆ |
| Nuclear density independent of mass number (R = R0 A1/3) asked 1× | Sample 2027 | ★★☆☆☆ |
| Bohr quantisation of angular momentum asked 2× | Board 2024Board 2026 | ★★☆☆☆ |
| Radius of nth Bohr orbit asked 2× | Board 2024Sample 2023 | ★★☆☆☆ |
| Binding energy curve regions and nuclear stability asked 1× | Sample 2026 | ★★☆☆☆ |
| Distance of closest approach in alpha scattering asked 1× | Sample 2026 | ★★☆☆☆ |
| Wavelength for an energy level transition asked 1× | Sample 2026 | ★★☆☆☆ |
| Bohr orbit angular momentum (nh/2π) and radius (∝ n2) asked 1× | Sample 2026 | ★★☆☆☆ |
| Binding energy per nucleon from mass defect asked 1× | Sample 2025 | ★☆☆☆☆ |
| Nuclear model from alpha scattering (small dense nucleus) asked 1× | Sample 2025 | ★☆☆☆☆ |
| Unified atomic mass unit asked 1× | Sample 2025 | ★☆☆☆☆ |
| Energy level transition: wavelength and photon emission rate asked 1× | Sample 2025 | ★☆☆☆☆ |
| Balanced fusion reaction equation asked 1× | Sample 2024 | ★☆☆☆☆ |
| Rutherford nuclear model; Bohr postulate asked 1× | Sample 2024 | ★☆☆☆☆ |
| Unified atomic mass unit, energy equivalent, binding energy per nucleon asked 1× | Sample 2024 | ★☆☆☆☆ |
| Rydberg constant from Balmer line wavelength asked 1× | Sample 2024 | ★☆☆☆☆ |
| Binding energy per nucleon curve and most stable nucleus asked 1× | Board 2026 | ★☆☆☆☆ |
| Series limit of Balmer series using Rydberg formula asked 1× | Board 2026 | ★☆☆☆☆ |
| Fusion needs very high temperature (thermonuclear) asked 1× | Board 2026 | ★☆☆☆☆ |
| Negative total energy means bound electron asked 1× | Board 2026 | ★☆☆☆☆ |
| Limitations of Bohr's model asked 1× | Board 2026 | ★☆☆☆☆ |
| Moderator slows down neutrons asked 1× | Sample 2023 | ★☆☆☆☆ |
| Differences between fusion and fission asked 1× | Sample 2023 | ★☆☆☆☆ |
| Controlled vs uncontrolled chain reaction asked 1× | Sample 2023 | ★☆☆☆☆ |
| Binding energy per nucleon curve and stability asked 1× | Sample 2023 | ★☆☆☆☆ |
| Bohr's postulates of quantisation and emission asked 1× | Sample 2023 | ★☆☆☆☆ |
| Mass defect, binding energy and their relation asked 1× | Sample 2023 | ★☆☆☆☆ |
| Fusion in stars; mass defect asked 1× | Board 2025 | ★☆☆☆☆ |
| Nuclear reactor: purpose, moderator, control rods for shutdown asked 1× | Board 2025 | ★☆☆☆☆ |
| Quantisation of angular momentum; significance of negative total energy asked 1× | Board 2025 | ★☆☆☆☆ |
| Hydrogen emission spectrum; Balmer series (transitions to n=2) asked 1× | Board 2024 | ★☆☆☆☆ |
| Moderator (graphite) and control rods (cadmium) in a reactor asked 1× | Board 2024 | ★☆☆☆☆ |
| Energy released in fusion via mass defect asked 1× | Board 2024 | ★☆☆☆☆ |
| Mass defect and binding energy of a nucleus asked 1× | Board 2024 | ★☆☆☆☆ |
| Bohr orbit velocity ∝ 1/n and radius ∝ n2 asked 1× | Board 2024 | ★☆☆☆☆ |
| Nuclear fusion in the Sun asked 1× | Board 2023 | ★☆☆☆☆ |
| Nuclear reactor components and functions asked 1× | Board 2023 | ★☆☆☆☆ |
| Bohr quantization of angular momentum (nh/2π) asked 1× | Board 2023 | ★☆☆☆☆ |
| Isotopes and definition of unified atomic mass unit asked 1× | Board 2023 | ★☆☆☆☆ |
| Binding energy per nucleon and its significance asked 1× | Board 2023 | ★☆☆☆☆ |
Electronic Devices (Semiconductors) · Electronic Devices
| Conductors have no forbidden band asked 3× | Board 2023Board 2025Sample 2027 | ★★★★☆ |
| Solar cell converts light to electrical energy asked 2× | Sample 2025Sample 2027 | ★★★☆☆ |
| LED threshold voltage relates to band gap and wavelength asked 2× | Sample 2026 | ★★★☆☆ |
| Forward-biased diode has low resistance asked 2× | Board 2026Sample 2027 | ★★★☆☆ |
| Doping to make extrinsic semiconductor asked 2× | Board 2026Sample 2027 | ★★★☆☆ |
| Potential barrier of a p-n junction asked 3× | Board 2024Board 2026Sample 2023 | ★★★☆☆ |
| Semiconductor resistance decreases with temperature asked 2× | Board 2025Sample 2027 | ★★★☆☆ |
| n-type semiconductor characteristics asked 2× | Board 2025Sample 2023 | ★★☆☆☆ |
| Reverse current due to minority carriers asked 1× | Sample 2027 | ★★☆☆☆ |
| Working of a solar cell (photovoltaic action) asked 1× | Sample 2027 | ★★☆☆☆ |
| Depletion region of a p-n junction asked 2× | Board 2024Sample 2023 | ★★☆☆☆ |
| Forward bias from circuit polarity asked 1× | Sample 2026 | ★★☆☆☆ |
| Direction of electron flow in a solar cell asked 1× | Sample 2026 | ★★☆☆☆ |
| Photon absorption/response depends on photon energy vs band gap asked 1× | Sample 2026 | ★★☆☆☆ |
| Full wave rectifier circuit and output waveform asked 2× | Board 2023Board 2025 | ★★☆☆☆ |
| Ideal diode: zero forward, infinite reverse resistance asked 1× | Sample 2025 | ★☆☆☆☆ |
| Identifying forward-biased diode from circuit polarity asked 1× | Sample 2025 | ★☆☆☆☆ |
| Reverse saturation current of a diode asked 1× | Sample 2025 | ★☆☆☆☆ |
| Potential barrier must be overcome for conduction asked 1× | Sample 2025 | ★☆☆☆☆ |
| Diode circuit analysis (conducting vs blocking branches) asked 1× | Sample 2025 | ★☆☆☆☆ |
| Semiconductor facts (metals have no forbidden band) asked 1× | Sample 2024 | ★☆☆☆☆ |
| Advantage of full wave over half wave rectifier asked 1× | Sample 2024 | ★☆☆☆☆ |
| LED and photodiode as special diodes asked 1× | Sample 2024 | ★☆☆☆☆ |
| LED forward biased, photodiode reverse biased asked 1× | Sample 2024 | ★☆☆☆☆ |
| LED circuit symbol asked 1× | Sample 2024 | ★☆☆☆☆ |
| Zener diode circuit symbol asked 1× | Board 2026 | ★☆☆☆☆ |
| Microammeter for small reverse current asked 1× | Board 2026 | ★☆☆☆☆ |
| Half wave rectifier circuit asked 1× | Board 2026 | ★☆☆☆☆ |
| Doping of semiconductors asked 1× | Sample 2023 | ★☆☆☆☆ |
| Reverse bias and reverse I-V characteristic asked 1× | Sample 2023 | ★☆☆☆☆ |
| Difference between p-type and n-type semiconductors asked 1× | Board 2025 | ★☆☆☆☆ |
| Zener diode as voltage regulator asked 1× | Board 2025 | ★☆☆☆☆ |
| Majority carriers in p-type are holes asked 1× | Board 2024 | ★☆☆☆☆ |
| Rectifier converts AC to DC asked 1× | Board 2024 | ★☆☆☆☆ |
| Forward bias of a diode asked 1× | Board 2024 | ★☆☆☆☆ |
| Forward bias I-V characteristic of a diode asked 1× | Board 2024 | ★☆☆☆☆ |
| Temperature dependence of semiconductor conductivity asked 1× | Board 2023 | ★☆☆☆☆ |
| p-type semiconductor from trivalent doping asked 1× | Board 2023 | ★☆☆☆☆ |
| Forbidden energy band (band gap) asked 1× | Board 2023 | ★☆☆☆☆ |
Importance = how often a topic was asked × how recent, with extra weight for the latest official sample paper.