Physics Formulas for Class 12 — Complete Chapter-Wise List
All Physics formulas for Class 12 CBSE — Electrostatics, Current Electricity, Magnetism, Optics, and Modern Physics chapter-wise.
Class 12 Physics has approximately 120–150 key formulas across 14 chapters. This complete chapter-wise list covers every formula you need for CBSE board exams, JEE Main, and NEET 2026. Bookmark and revise daily.
Chapter 1: Electric Charges & Fields
| Formula | Description |
|---|---|
| F = kq₁q₂/r² | Coulomb's law (k = 9 × 10⁹ Nm²/C²) |
| E = F/q = kQ/r² | Electric field due to point charge |
| E (dipole, axial) = 2kp/r³ | Field on axis of dipole (r ≫ a) |
| E (dipole, equatorial) = kp/r³ | Field on equatorial line of dipole |
| τ = pE sinθ | Torque on dipole in uniform field |
| ∮E·dA = q/ε₀ | Gauss's law |
| E = σ/2ε₀ | Field due to infinite plane sheet of charge |
| E = σ/ε₀ | Field between two parallel plates |
Chapter 2: Electrostatic Potential & Capacitance
| Formula | Description |
|---|---|
| V = kQ/r | Potential due to point charge |
| V = −∫E·dr | Relation between V and E |
| E = −dV/dr | Electric field from potential |
| W = qΔV | Work done in moving charge |
| U = kq₁q₂/r | Potential energy of two charges |
| C = Q/V | Capacitance definition |
| C = ε₀A/d | Parallel plate capacitor |
| C = ε₀KA/d | With dielectric (K = dielectric constant) |
| Series: 1/C = 1/C₁ + 1/C₂ | Capacitors in series |
| Parallel: C = C₁ + C₂ | Capacitors in parallel |
| U = ½CV² = ½QV = Q²/2C | Energy stored in capacitor |
Chapter 3: Current Electricity
| Formula | Description |
|---|---|
| V = IR | Ohm's law |
| R = ρl/A | Resistance in terms of resistivity |
| ρ = ρ₀(1 + αΔT) | Temperature dependence of resistivity |
| Series: R = R₁ + R₂ + R₃ | Resistors in series |
| Parallel: 1/R = 1/R₁ + 1/R₂ | Resistors in parallel |
| P = VI = I²R = V²/R | Electric power |
| H = I²Rt | Joule's law of heating |
| ε = V + Ir | EMF with internal resistance |
| Wheatstone: P/Q = R/S | Balance condition |
Apply these formulas in practice
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Practise Physics — FreeChapter 4: Moving Charges & Magnetism
| Formula | Description |
|---|---|
| F = qv × B = qvB sinθ | Force on moving charge in magnetic field |
| r = mv/qB | Radius of circular motion in B field |
| F = BIl sinθ | Force on current-carrying conductor |
| dB = μ₀Idl sinθ / 4πr² | Biot-Savart law |
| B = μ₀I/2R | Field at centre of circular loop |
| B = μ₀nI | Field inside solenoid (n = turns/length) |
| ∮B·dl = μ₀I | Ampere's circuital law |
| τ = NIAB sinθ = M × B | Torque on current loop |
Chapter 5: Magnetism & Matter
| Formula | Description |
|---|---|
| M = m × 2l | Magnetic moment of bar magnet |
| B (axial) = μ₀2M/4πr³ | Field on axis of bar magnet |
| B (equatorial) = μ₀M/4πr³ | Field on equatorial line |
| χ = M/H | Magnetic susceptibility |
| μᵣ = 1 + χ | Relative permeability |
Chapter 6: Electromagnetic Induction
| Formula | Description |
|---|---|
| ε = −dΦ/dt | Faraday's law of EMI |
| Φ = BA cosθ | Magnetic flux |
| ε = BLv | Motional EMF |
| ε = NBAω sinωt | EMF in rotating coil (AC generator) |
| L = NΦ/I | Self-inductance |
| ε = −L(dI/dt) | Self-induced EMF |
| U = ½LI² | Energy stored in inductor |
| M = μ₀n₁n₂Al | Mutual inductance of two solenoids |
Chapter 7: Alternating Current
| Formula | Description |
|---|---|
| Iᵣₘₛ = I₀/√2 | RMS value of current |
| Vᵣₘₛ = V₀/√2 | RMS value of voltage |
| Xc = 1/ωC = 1/2πfC | Capacitive reactance |
| XL = ωL = 2πfL | Inductive reactance |
| Z = √(R² + (XL − Xc)²) | Impedance of LCR circuit |
| tanφ = (XL − Xc)/R | Phase angle |
| f₀ = 1/(2π√LC) | Resonant frequency |
| P = VᵣₘₛIᵣₘₛ cosφ | Average power (cosφ = power factor) |
| Vₛ/Vₚ = Nₛ/Nₚ | Transformer equation |
Chapter 9: Ray Optics
| Formula | Description |
|---|---|
| 1/v − 1/u = 1/f | Mirror formula |
| m = −v/u | Magnification (mirror) |
| n₁ sinθ₁ = n₂ sinθ₂ | Snell's law |
| 1/v − 1/u = 1/f | Lens formula |
| 1/f = (n−1)(1/R₁ − 1/R₂) | Lensmaker's equation |
| P = 1/f (in metres) | Power of lens (in dioptres) |
| P = P₁ + P₂ − dP₁P₂ | Combination of thin lenses |
| sinC = 1/n | Critical angle for total internal reflection |
Chapter 10: Wave Optics
| Formula | Description |
|---|---|
| β = λD/d | Fringe width in YDSE |
| Bright: d sinθ = nλ | Condition for constructive interference |
| Dark: d sinθ = (2n−1)λ/2 | Condition for destructive interference |
| a sinθ = nλ | Single slit diffraction minima |
| I = I₀ cos²θ | Malus's law (polarisation) |
| tanθₚ = n | Brewster's law |
Chapter 11: Dual Nature of Radiation & Matter
| Formula | Description |
|---|---|
| E = hν = hc/λ | Energy of photon |
| KEₘₐₓ = hν − φ | Photoelectric equation (Einstein) |
| eV₀ = hν − φ | Stopping potential |
| ν₀ = φ/h | Threshold frequency |
| λ = h/mv = h/p | de Broglie wavelength |
| λ = h/√(2mKE) | de Broglie wavelength from KE |
Chapter 12: Atoms
| Formula | Description |
|---|---|
| rₙ = 0.53n²/Z Å | Bohr radius of nth orbit |
| Eₙ = −13.6Z²/n² eV | Energy of nth orbit |
| vₙ = 2.18 × 10⁶ Z/n m/s | Velocity in nth orbit |
| 1/λ = RZ²(1/n₁² − 1/n₂²) | Wavelength of spectral lines |
Chapter 13: Nuclei
| Formula | Description |
|---|---|
| R = R₀A^(1/3) | Nuclear radius (R₀ = 1.2 fm) |
| Δm = Zm_p + (A−Z)m_n − M | Mass defect |
| BE = Δm × 931.5 MeV | Binding energy |
| N = N₀e^(−λt) | Radioactive decay law |
| t₁/₂ = 0.693/λ | Half-life |
| τ = 1/λ | Mean life |
| A = λN = A₀e^(−λt) | Activity |
Formulas based on CBSE Class 12 Physics syllabus 2025–2026. Also applicable for JEE Main and NEET. Some advanced formulas (not in CBSE but in JEE/NEET) are not included here. Verify with your specific exam syllabus. Last updated: February 2026.
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Try Super Tutor — It's FreeFrequently Asked Questions
How many formulas are there in Class 12 Physics?
Class 12 Physics has approximately 120–150 key formulas across 14 chapters. The most formula-heavy chapters are Electrostatics (~25 formulas), Current Electricity (~15 formulas), Magnetism (~20 formulas), and Optics (~20 formulas). Understanding the derivation helps you recall formulas during exams.
Which Class 12 Physics chapter has the most formulas?
Electrostatics has the most formulas — Coulomb's law, electric field for various configurations, potential, capacitance, and energy stored. Magnetism (Biot-Savart, Ampere's law, force on conductors) is a close second. These two chapters combined carry 15–20 marks in the board exam.
Are Physics formulas given in the CBSE board exam?
No, CBSE does not provide a formula sheet. You must memorise all standard formulas. However, for derivation-based questions, the examiner checks your approach and steps, not just the final formula. If you forget a formula but show the correct derivation method, you can still earn partial marks.
How to memorise Physics formulas effectively?
Best techniques: (1) Derive each formula at least once — understanding the derivation makes it stick, (2) Group related formulas (e.g., all capacitor formulas together), (3) Practise 5 numerical problems per formula, (4) Create a formula sheet and revise daily, (5) Use dimensional analysis to verify — if units don't match, the formula is wrong.
Which formulas are most important for JEE/NEET?
Beyond board exam formulas, JEE/NEET frequently test: Gauss's law applications, complex circuit problems (Kirchhoff's), electromagnetic induction (Faraday's law applications), and Modern Physics (photoelectric effect, Bohr model, nuclear reactions). These chapters carry 60–70 marks in both exams.