In CBSE Class 12 Physics, numericals are 40-50% of your paper. Numerical types repeat year after year — master the standard types and score 35+ out of 70 on numericals alone.
Numerical Hotspots by Chapter
| Chapter | Numerical Types That Repeat |
|---|---|
| Current Electricity | Kirchhoff laws (2-loop), Wheatstone bridge, Potentiometer null point |
| Ray Optics | Lens-mirror combination, magnification, TIR critical angle |
| Electrostatics | Electric field, potential energy, capacitor combinations |
| Magnetism | Force on moving charge, torque on current loop, solenoid field |
| EMI and AC | LCR resonant frequency, power factor, peak vs RMS |
| Dual Nature | Stopping potential, de Broglie wavelength, photoelectric threshold |
| Atoms and Nuclei | Energy of Bohr orbit, binding energy, half-life |
The 4-Line Step-Marking Format
- 1.Given: write all known quantities with SI units
- 2.Formula: write the formula before substituting anything
- 3.Substitution: put numbers in with units
- 4.Answer: box the final answer with correct unit
Tip
CBSE awards 1 mark each for: correct formula, correct substitution, and correct answer. Even if your final answer is wrong due to arithmetic, you score 2 out of 3 marks if formula and substitution are right.
Most Common Numerical Mistakes
- Mixing eV and Joules — 1 eV = 1.6 x 10^-19 J
- Dropping units mid-calculation
- Not drawing the circuit before applying Kirchhoff laws
- Wrong sign conventions for mirror vs lens formula