Class 12 Physics Formula Sheet 2025 – All Chapters with Examples

Physics is the most conceptual and numerical subject in Class 12 Science. Whether you’re preparing for the CBSE Board Exam, JEE Main, or NEET, mastering formulas is the key to scoring high. Physics formulas act as shortcuts that help you quickly solve numerical problems and understand physical phenomena.

This Class 12 Physics Formula Sheet covers all chapters from the NCERT syllabus, arranged chapter-wise, with important formulas, units, and examples for each topic. Each formula is explained with a simple example so you can understand how to apply it in your exams.

Class 12 Physics Formula Sheet 2025 – All Chapters with Examples

Chapter 1: Electric Charges and Fields

Important Formulas

1. Coulomb’s Law:

   F=14πε0⋅q1q2r2F = \frac{1}{4\pi \varepsilon_0} \cdot \frac{q_1 q_2}{r^2}F=4πε0​1​⋅r2q1​q2​​

   Example:
   If q1=q2=1 μCq_1 = q_2 = 1 \, \mu Cq1​=q2​=1μC and $r=1m$,
   F=9×109×(10−6)2=9×10−3NF = 9 \times 10^9 \times (10^{-6})^2 = 9 \times 10^{-3} NF=9×109×(10−6)2=9×10−3N

2. Electric Field due to a Point Charge:

   E=14πε0⋅qr2E = \frac{1}{4\pi \varepsilon_0} \cdot \frac{q}{r^2}E=4πε0​1​⋅r2q​

3. Electric Dipole Moment:

   $$p=q\times 2l$$

4. Electric Field due to a Dipole (Axial Line):

   E=14πε0⋅2pr3E = \frac{1}{4\pi \varepsilon_0} \cdot \frac{2p}{r^3}E=4πε0​1​⋅r32p​

Chapter 2: Electrostatic Potential and Capacitance

Important Formulas

1. Potential due to a Point Charge:

   V=14πε0⋅qrV = \frac{1}{4\pi \varepsilon_0} \cdot \frac{q}{r}V=4πε0​1​⋅rq​

2. Potential Energy of Two Point Charges:

   U=14πε0⋅q1q2rU = \frac{1}{4\pi \varepsilon_0} \cdot \frac{q_1 q_2}{r}U=4πε0​1​⋅rq1​q2​​

3. Capacitance of Parallel Plate Capacitor:

   C=ε0AdC = \varepsilon_0 \frac{A}{d}C=ε0​dA​

4. Energy Stored in a Capacitor:

   U=12CV2U = \frac{1}{2} C V^2U=21​CV2

Example:
If $C=10\mu F$ and $V=50V$,
U=0.5×10−5×502=0.0125 JU = 0.5 \times 10^{-5} \times 50^2 = 0.0125 \, JU=0.5×10−5×502=0.0125J

Chapter 3: Current Electricity

Important Formulas

1. Ohm’s Law:

   $$V=IR$$

2. Resistance in Series:

   Req=R1+R2+R3R_{eq} = R_1 + R_2 + R_3Req​=R1​+R2​+R3​

3. Resistance in Parallel:

   1Req=1R1+1R2+1R3\frac{1}{R_{eq}} = \frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3}Req​1​=R1​1​+R2​1​+R3​1​

4. Power:

   P=VI=I2R=V2RP = VI = I^2 R = \frac{V^2}{R}P=VI=I2R=RV2​

5. Resistivity:

   R=ρlAR = \rho \frac{l}{A}R=ρAl​

Example:
If a 2 m long wire has area 1mm21 mm^21mm2 and resistivity 2×10−8 Ωm2 \times 10^{-8} \, \Omega m2×10−8Ωm,
R=2×10−8×210−6=0.04 ΩR = 2 \times 10^{-8} \times \frac{2}{10^{-6}} = 0.04 \, \OmegaR=2×10−8×10−62​=0.04Ω

Chapter 4: Moving Charges and Magnetism

Important Formulas

1. Magnetic Force on Moving Charge:

   $$F=qvB\sin \theta$$

2. Lorentz Force:

   F⃗=q(E⃗+v⃗×B⃗)\vec{F} = q(\vec{E} + \vec{v} \times \vec{B})F=q(E+v×B)

3. Magnetic Field due to Straight Current:

   B=μ0I2πrB = \frac{\mu_0 I}{2\pi r}B=2πrμ0​I​

4. Force on Current-Carrying Conductor:

   $$F=BIL\sin \theta$$

Example:
For $B=0.5T,I=2A,L=1m,\theta =90°$:
$F=0.5\times 2\times 1=1N$

Chapter 5: Magnetism and Matter

1. Magnetic Dipole Moment:

   $$M=IA$$

2. Torque on Magnetic Dipole:

   $$\tau =MB\sin \theta$$

3. Magnetic Field at Axial Point of Bar Magnet:

   B=μ04π⋅2Mr3B = \frac{\mu_0}{4\pi} \cdot \frac{2M}{r^3}B=4πμ0​​⋅r32M​

Example:
If M=0.1 A⋅m2M = 0.1 \, A·m^2M=0.1A⋅m2, $r=0.2m$:
B=10−7×2×0.1(0.2)3=2.5×10−6TB = 10^{-7} \times \frac{2 \times 0.1}{(0.2)^3} = 2.5 \times 10^{-6} TB=10−7×(0.2)32×0.1​=2.5×10−6T

Chapter 6: Electromagnetic Induction

1. Faraday’s Law:

   ε=−dΦdt\varepsilon = -\frac{d\Phi}{dt}ε=−dtdΦ​

2. Lenz’s Law:
   Direction of induced emf opposes the change causing it.

3. Self Inductance:

   ε=−Ldidt\varepsilon = -L \frac{di}{dt}ε=−Ldtdi​

4. Energy Stored in Inductor:

   U=12LI2U = \frac{1}{2} L I^2U=21​LI2

Example:
If $L=0.5H$ and $I=2A$:
$U=0.5\times 0.5\times 4=1J$

Chapter 7: Alternating Current

1. Instantaneous Value of AC:

   i=i0sin⁡(ωt)i = i_0 \sin(\omega t)i=i0​sin(ωt)

2. RMS Value:

   Irms=i02I_{rms} = \frac{i_0}{\sqrt{2}}Irms​=2​i0​​

3. Power in AC Circuit:

   $$P=VI\cos \varphi$$

4. Impedance in LCR Circuit:

   Z=R2+(XL−XC)2Z = \sqrt{R^2 + (X_L – X_C)^2}Z=R2+(XL​−XC​)2​

   where XL=ωLX_L = \omega LXL​=ωL, XC=1ωCX_C = \frac{1}{\omega C}XC​=ωC1​

Example:
If $R=3\Omega ,L=0.1H,C=100\mu F,f=50Hz$, find Z.
XL=2πfL=31.4Ω,XC=12πfC=31.8ΩX_L = 2\pi fL = 31.4Ω, X_C = \frac{1}{2\pi fC} = 31.8ΩXL​=2πfL=31.4Ω,XC​=2πfC1​=31.8Ω
So Z=32+(31.4−31.8)2≈3.03ΩZ = \sqrt{3^2 + (31.4-31.8)^2} ≈ 3.03ΩZ=32+(31.4−31.8)2​≈3.03Ω

Chapter 8: Electromagnetic Waves

1. Speed of Light:

   c=1μ0ε0c = \frac{1}{\sqrt{\mu_0 \varepsilon_0}}c=μ0​ε0​​1​

2. Relation between Electric and Magnetic Fields:

   E0B0=c\frac{E_0}{B_0} = cB0​E0​​=c

3. Types of EM Waves:
   Radio → Microwave → Infrared → Visible → UV → X-rays → Gamma

Chapter 9: Ray Optics and Optical Instruments

1. Mirror Formula:

   1f=1v+1u\frac{1}{f} = \frac{1}{v} + \frac{1}{u}f1​=v1​+u1​

2. Magnification (Mirror):

   m=−vum = -\frac{v}{u}m=−uv​

3. Lens Formula:

   1f=1v−1u\frac{1}{f} = \frac{1}{v} – \frac{1}{u}f1​=v1​−u1​

4. Magnification (Lens):

   m=vum = \frac{v}{u}m=uv​

5. Power of Lens:

   P=1f(in meters)P = \frac{1}{f (in \, meters)}P=f(inmeters)1​

Example:
If $f=0.25m$, then $P=4D$

Chapter 10: Wave Optics

1. Path Difference:

   $$\Delta x=d\sin \theta$$

2. Condition for Constructive Interference:

   $$\Delta x=n\lambda$$

3. Condition for Destructive Interference:

   Δx=(2n+1)λ2\Delta x = (2n+1)\frac{\lambda}{2}Δx=(2n+1)2λ​

4. Angular Fringe Width (Young’s Experiment):

   β=λDd\beta = \frac{\lambda D}{d}β=dλD​

Example:
If $\lambda =600nm,D=1m,d=0.1mm$:
β=6×10−3m=0.6cm\beta = 6 \times 10^{-3} m = 0.6cmβ=6×10−3m=0.6cm

Chapter 11: Dual Nature of Radiation and Matter

1. Einstein’s Photoelectric Equation:

   hν=hν0+12mv2h\nu = h\nu_0 + \frac{1}{2}mv^2hν=hν0​+21​mv2

2. De Broglie Wavelength:

   λ=hp=hmv\lambda = \frac{h}{p} = \frac{h}{mv}λ=ph​=mvh​

3. Kinetic Energy of Emitted Electron:

   K.E=h(ν−ν0)K.E = h(\nu – \nu_0)K.E=h(ν−ν0​)

Example:
If $h\nu =5eV$ and hν0=2eVh\nu_0 = 2eVhν0​=2eV,
$K.E=3eV$

Chapter 12: Atoms

1. Energy Levels of Hydrogen Atom:

   En=−13.6Z2n2 eVE_n = -13.6 \frac{Z^2}{n^2} \, eVEn​=−13.6n2Z2​eV

2. Radius of nth Orbit:

   rn=n2a0r_n = n^2 a_0rn​=n2a0​

   where a0=0.529A˚a_0 = 0.529Åa0​=0.529A˚

3. Velocity of Electron in nth Orbit:

   vn=e22ε0h⋅1nv_n = \frac{e^2}{2\varepsilon_0 h} \cdot \frac{1}{n}vn​=2ε0​he2​⋅n1​

Example:
For n=1, E1=−13.6eVE_1 = -13.6eVE1​=−13.6eV; for n=2, E2=−3.4eVE_2 = -3.4eVE2​=−3.4eV

Chapter 13: Nuclei

1. Mass Defect:

   Δm=Zmp+(A−Z)mn−M\Delta m = Zm_p + (A – Z)m_n – MΔm=Zmp​+(A−Z)mn​−M

2. Binding Energy:

   EB=(Δm)c2E_B = (\Delta m)c^2EB​=(Δm)c2

3. Radioactive Decay Law:

   N=N0e−λtN = N_0 e^{-\lambda t}N=N0​e−λt

4. Half-life:

   T1/2=0.693λT_{1/2} = \frac{0.693}{\lambda}T1/2​=λ0.693​

Example:
If λ=0.001s−1\lambda = 0.001 s^{-1}λ=0.001s−1, then T1/2=693sT_{1/2} = 693sT1/2​=693s

Chapter 14: Semiconductor

Electronics

1. Current Relation (Diode Equation):

   I=I0(eeVkT−1)I = I_0 (e^{\frac{eV}{kT}} – 1)I=I0​(ekTeV​−1)

2. Ohm’s Law in Diode Circuit:
   $V=IR$

3. Logic Gates:

   • AND: Output = A·B

   • OR: Output = A + B

   • NOT: Output = Aˉ\bar{A}Aˉ

Example:
For AND gate, if A=1 and B=0 → Output = 0

Conclusion

Physics is all about understanding and applying concepts — and formulas are the language of Physics. This comprehensive Class 12 Physics Formula Sheet covers every chapter from Electric Charges to Semiconductors, with real examples for better understanding.

Revise these formulas daily, practice numerical problems, and you’ll find even the toughest questions easy to solve. Remember, concept clarity + formula mastery = success in Physics.

FAQs

1. How can I memorize all Class 12 Physics formulas easily?

Use flashcards, regular practice, and write formulas repeatedly while solving problems.

2. Are these formulas enough for the CBSE 2025 exam?

Yes, all key formulas from the NCERT syllabus are included.

3. Which chapters are most important for JEE or NEET?

Current Electricity, Ray Optics, Electromagnetic Induction, and Dual Nature are highly scoring.

4. How to use formulas in numerical problems?

Always start by identifying known and unknown quantities, then select the right formula logically.

5. Can I download this formula sheet as PDF?

Yes, you can easily copy and save this sheet as a Physics revision PDF for quick access.

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