A Hand Book of Formulae for 10+2 Physics

Class 12 Physics – Formula Handbook

CBSE + PSEB | Session 2026–27

Table of Contents

  1. Electric Charges and Fields
  2. Electrostatic Potential & Capacitance
  3. Current Electricity
  4. Moving Charges & Magnetism
  5. Magnetism & Matter
  6. Electromagnetic Induction
  7. Alternating Current
  8. Electromagnetic Waves
  9. Ray Optics
  10. Wave Optics
  11. Dual Nature of Radiation
  12. Atoms
  13. Nuclei
  14. Semiconductors
  15. Communication Systems

Chapter 1: Electric Charges and Fields

  • Coulomb’s Law: F = k q1q2 / r²
  • k = 1 / (4πϵ₀)
  • Electric Field: E = F / q
  • E (point charge): E = kQ / r²
  • Dipole Moment: p = q × 2l
  • Axial Field: E = (1 / 4πϵ₀)(2p / r³)
  • Equatorial Field: E = (1 / 4πϵ₀)(p / r³)
  • Gauss’s Law: Φ = ∮E·dS = Q / ϵ₀

Chapter 2: Electrostatic Potential & Capacitance

  • Potential: V = kQ / r
  • E = −dV/dr
  • Capacitance: C = Q / V
  • Parallel Plate: C = ϵ₀A / d
  • With Dielectric: C = kϵ₀A / d
  • Series: 1/C = 1/C₁ + 1/C₂ + …
  • Parallel: C = C₁ + C₂ + …
  • Energy: U = ½CV² = Q²/(2C)

Chapter 3: Current Electricity

  • I = Q / t
  • Drift Velocity: vd = I / (nAe)
  • Ohm’s Law: V = IR
  • Resistance: R = ρL / A
  • Series: R = R₁ + R₂ + …
  • Parallel: 1/R = 1/R₁ + 1/R₂ + …
  • Power: P = VI = I²R = V²/R
  • V = ε − Ir

Chapter 4: Moving Charges & Magnetism

  • Force on charge: F = qvB sinθ
  • Force on wire: F = BIL sinθ
  • Parallel currents: F/L = μ₀I₁I₂ / (2πd)
  • Long wire field: B = μ₀I / (2πr)
  • Circular loop: B = μ₀I / (2R)
  • Torque: τ = nBIA sinθ
  • Radius: r = mv / (qB)

Chapter 5: Magnetism & Matter

  • Dipole Moment: M = m × 2l
  • Torque: τ = MB sinθ
  • Potential Energy: U = −MB cosθ
  • Magnetization: M = magnetic moment / volume
  • Susceptibility: χ = M / H
  • μr = 1 + χ

Chapter 6: Electromagnetic Induction

  • Faraday: ε = −dΦ/dt
  • Flux: Φ = BA cosθ
  • Rod EMF: ε = Blv
  • Self Induction: ε = −L dI/dt
  • Energy: U = ½LI²
  • Mutual Induction: ε₂ = −M dI₁/dt

Chapter 7: Alternating Current

  • I = I₀ sinωt
  • Irms = I₀/√2
  • XL = ωL
  • XC = 1/(ωC)
  • Z = √(R² + (XL − XC)²)
  • cosφ = R/Z
  • P = VrmsIrmscosφ
  • Resonance: ω₀ = 1/√(LC)

Chapter 8: Electromagnetic Waves

  • c = 1/√(μ₀ϵ₀)
  • c = λν
  • uE = ½ϵ₀E²
  • uB = B²/(2μ₀)
  • I ∝ E₀²

Chapter 9: Ray Optics

  • n = c/v
  • Snell: n₁ sinθ₁ = n₂ sinθ₂
  • Mirror: 1/f = 1/v + 1/u
  • m = −v/u
  • Lens: 1/f = 1/v − 1/u
  • Power: P = 1/f
  • Peq = P₁ + P₂ + …

Chapter 10: Wave Optics

  • β = λD/d
  • Maxima: Δx = nλ
  • Minima: Δx = (2n+1)λ/2
  • Malus: I = I₀ cos²θ

Chapter 11: Dual Nature

  • E = hν = hc/λ
  • hν = φ + ½mv²
  • eV₀ = ½mv²
  • λ = h/p = h/mv
  • λ = h/√(2meV)

Chapter 12: Atoms

  • rn = n²a₀
  • En = −13.6/n² eV
  • hν = Ei − Ef
  • 1/λ = R(1/nf² − 1/ni²)

Chapter 13: Nuclei

  • Δm = Zmp + Nmn − M
  • B.E. = Δm c²
  • A = λN
  • N = N₀ e−λt
  • T1/2 = 0.693/λ
  • τ = 1/λ

Chapter 14: Semiconductors

  • σ = neμe + peμh
  • ρ = 1/σ
  • I ≈ I₀(eeV/ηkT − 1)
  • β = IC/IB

Chapter 15: Communication Systems

  • Modulation Index: μ = (Amax − Amin)/(Amax + Amin)
  • Bandwidth (AM): BW = 2fm
  • SNR = Psignal / Pnoise
  • Nyquist Rate: Rmax = 2B log₂M

End of Class 12 Physics Formula Handbook

Scroll to Top