Class 12 Physics Revision for NEET 2026 In One Shot By PW

Class 12 Physics revision for NEET 2026 requires focused practice of Electrostatics, Current Electricity, Capacitors, Magnetism, Electromagnetic Induction, Alternating Current, Electromagnetic Waves, Semiconductors, Wave Optics, Modern Physics and Ray Optics. Use formulas, standard results, graphs and sign conventions for quick revision, and practise PYQs and questions with PW’s NEET resources.

With PW's NEET complete class 12 Physics preparation resources, you can revise important Class 12 Physics concepts, practise questions and work through NEET PYQs. Focused revision can help identify formula-based errors, conceptual gaps and topics that require additional practice.

Electrostatics: Core Concepts and Formulas

Electrostatics covers electric charges, electric fields, electric potential, electric dipoles and Gauss's law. During revision, focus on the standard formulas as well as the conditions associated with conductors, charged spheres, electric flux and null points.

Important relations include:

• Coulomb's law: F = kq1q2/r²

• Electric field due to a point charge: E = kq/r²

• Electric potential: V = kq/r

• Potential energy of two charges: U = kq1q2/r

• Dipole moment: p = qd

• Torque on a dipole: τ = pE sin θ

• Dipole potential energy: U = −pE cos θ

For a conductor in electrostatic equilibrium:

• Electric field inside the conducting material is zero.

• Excess charge remains on the surface.

• Potential remains constant throughout the conductor.

For a hollow sphere, the electric field inside is zero, but potential is constant and equal to the surface potential. For a solid sphere, the electric field at the centre is zero, but the potential at the centre is not zero.

Gauss's Law and Electric Flux

Gauss's law is:

Φ = qenclosed/ε0

Only the enclosed charge is used in this expression. In E cos θ, the angle is measured between the electric field and the area vector, not the physical surface.

For null points, remember:

Memory Tip: For same-sign charges, the null point lies between them. For opposite-sign charges, it lies outside, on the side of the smaller-magnitude charge.

Current Electricity: Circuit Analysis

Current Electricity requires revision of resistance, resistivity, current density, drift current, electrical power and heat production. Along with the formulas, focus on how current behaves in conductors and how ideal electrical instruments are connected in a circuit.

The main formulas are:

• Ohm's law: V = IR

• Resistance: R = ρL/A

• Current density: J = I/A

• Drift current: I = nqAvd

• Power: P = I²R = V²/R

• Heat produced: H = I²Rt

For a tapered conductor, current remains constant. If area decreases, drift velocity and current density increase.

Instruments and Bridges

Ideal electrical instruments have specific resistance conditions and circuit connections:

• An ideal ammeter has zero resistance and is connected in series.

• An ideal voltmeter has infinite resistance and is connected in parallel.

• A galvanometer becomes an ammeter using a low resistance shunt in parallel.

• A galvanometer becomes a voltmeter using a large resistance in series.

A Wheatstone bridge is balanced when:

R1/R2 = R3/R4

The current through the central branch is then zero. In a metre bridge, always use the actual wire length and calculate the shift by subtracting the old and new null-point positions.

Capacitors: Charge, Energy and Dielectrics

Capacitors involve relationships between charge, capacitance, potential difference and stored energy. Revision should cover the basic equations, series and parallel combinations, the effect of dielectrics and the behaviour of capacitors in an RC circuit.

The basic relations are:

• Q = CV

• C = ε0A/d

• Energy: U = 1/2 CV² = Q²/2C = 1/2 QV

For capacitors:

• Series combination: charge is the same.

• Parallel combination: potential difference is the same.

Memory Tip: Series capacitors have the same charge; parallel capacitors have the same voltage.

Effect of Dielectric

When a dielectric is completely inserted: C' = KC

If the battery remains connected, voltage remains constant. Charge and stored energy increase in proportion to capacitance.

If the battery is disconnected, charge remains constant, while voltage, electric field and energy decrease by a factor of K.

For a partially inserted dielectric slab:

C' = ε0A/[d − t(1 − 1/K)]

RC Circuit

An RC circuit should be revised through its initial and final conditions.

• At t = 0, an uncharged capacitor acts like a wire.

• At t = infinity, a charged capacitor acts like an open circuit.

Charging equation:

q = q0(1 − exp(−t/RC))

Discharging equation:

q = q0 exp(−t/RC)

Magnetism: High-Yield Results

Magnetism includes magnetic fields produced by current-carrying conductors, forces on charges and wires, magnetic moments and the motion of charged particles. During revision, connect each formula with the physical situation in which it is used.

Important magnetic-field formulas include:

• Infinite straight wire: B = μ0I/(2πr)

• Circular loop at centre: B = μ0I/(2r)

• Solenoid: B = μ0nI

• Force on a wire: F = ILB sin θ

• Force on a charge: F = qvB sin θ

• Circular-path radius: r = mv/qB

• Time period: T = 2πm/qB

• Magnetic moment: m = NIA

• Torque: τ = mB sin θ

For two parallel current-carrying wires:

• Same-direction currents attract.

• Opposite-direction currents repel.

Motion of Charged Particles in a Magnetic Field

A particle entering a magnetic field at an angle follows a helical path. The perpendicular velocity component produces circular motion, while the parallel component produces forward motion.

Magnetic force does no work, so speed and kinetic energy remain constant.

For an undeviated charged particle in crossed electric and magnetic fields:

qE = qvB

Therefore:

E = vB

Electromagnetic Induction

Electromagnetic Induction focuses on magnetic flux, induced emf, Faraday's law, Lenz's law, motional emf and energy stored in an inductor. Revision should also include the conditions under which induced emf becomes zero and the relationship between flux change and charge transferred.

The important relations are:

• Magnetic flux: Φ = BA cos θ

• Faraday's law: emf = −dΦ/dt

• Motional emf: emf = BLv

• Inductor emf: emf = −L dI/dt

• Energy in an inductor: U = 1/2 LI²

The angle in magnetic flux is measured with the area vector. If a loop moves entirely inside a uniform magnetic field without changing its area or orientation, flux remains constant and induced emf is zero.

Lenz's law states that the induced current opposes the change in magnetic flux, not the flux itself.

Memory Tip: Increase ko increase mat hone do; decrease ko decrease mat hone do.

In a moving-rod problem, constant velocity occurs when:

ILB = mg

For total charge transferred through a resistance:

q = change in flux/R

Alternating Current: LCR Circuit and Resonance

Alternating Current revision includes impedance, inductive and capacitive reactance, power factor, phase relationships and resonance. The LCR circuit is particularly important for remembering how impedance and current behave at resonance.

For a series LCR circuit:

Z = square root of [R² + (XL − XC)²]

where:

• XL = ωL

• XC = 1/(ωC)

The power factor is:

cos φ = R/Z

Resonance in an LCR Circuit

At resonance:

• XL = XC

• Z = R

• Phase angle is zero.

• Power factor is one.

• Current is maximum.

The resonance frequency is:

f0 = 1/[2π square root of LC]

The phase relationships are:

• Resistor: voltage and current are in phase.

• Inductor: voltage leads current by 90 degrees.

• Capacitor: current leads voltage by 90 degrees.

Average power is:

P = Vrms Irms cos φ

Electromagnetic Waves: Important Relations

Electromagnetic waves are produced by accelerated charges. Their electric field, magnetic field and direction of propagation have a specific perpendicular relationship, making this chapter important for revising standard results and relationships.

Electromagnetic waves have the following key relations:

• Wave speed: c = 1/square root of μ0ε0

• Field amplitudes: E0 = cB0

• Displacement current: ID = ε0 dΦE/dt

• Intensity: I = 1/2 ε0E0²c

The electric and magnetic energy densities are equal: uE = uB

The wavelength order is: Radio waves → Microwaves → Infrared → Ultraviolet → X-rays → Gamma rays

Semiconductors and Logic Gates

Semiconductors require revision of doping, P-type and N-type semiconductors, diode biasing and the working conditions of important semiconductor devices. Logic-gate expressions and De Morgan's law should also be revised together for quick recall.

Important facts include:

• Pentavalent doping produces an N-type semiconductor.

• Trivalent doping produces a P-type semiconductor.

• Both P-type and N-type semiconductors are electrically neutral overall.

• Forward bias narrows the depletion layer.

• Reverse bias widens the depletion layer.

• An LED operates in forward bias.

• A photodiode operates in reverse bias.

• A Zener diode operates in reverse breakdown and maintains nearly constant voltage.

Logic Gates

The important logic expressions are:

• OR: Y = A + B

• AND: Y = A.B

• NOT: Y = complement of A

• NAND: Y = complement of A.B

• De Morgan's law: complement of A + B = complement of A multiplied by complement of B

Wave Optics: YDSE and Important Results

Wave Optics includes Young's double-slit experiment and the relationships between path difference, fringe width, wavelength and refractive index. Focus on the standard results and how fringe width changes with the medium and wavelength.

In YDSE:

• Path difference for bright fringe: nλ

• Path difference for dark fringe: (2n + 1)λ/2

• Fringe width: β = λD/d

• Slab-induced path difference: (μ − 1)t

Fringe width decreases in a medium by the factor of refractive index. Violet light produces narrower fringes than red light.

Modern Physics: Photons, Photoelectric Effect and Bohr Model

Modern Physics includes photon-related equations, the photoelectric effect and the Bohr model of atoms. Revision should focus on the standard equations and the relationships between photon energy, momentum, kinetic energy and atomic quantities.

Photons and Photoelectric Effect

For photons:

• Energy: E = hc/λ

• Momentum: p = h/λ

Photoelectric equation:

E = work function + maximum kinetic energy

Maximum kinetic energy is:

Kmax = eV0

Bohr Model

For Bohr atoms:

• Radius: r is proportional to n²/Z.

• Speed: v is proportional to Z/n.

• Angular momentum: L = nh/(2π)

• Spectral series: Lyman ends at n = 1, Balmer at n = 2, and Paschen at n = 3.

Ray Optics: Important Formulas and Concepts

Ray Optics requires careful revision of mirror and lens formulas, magnification, prism deviation, critical angle and apparent depth. Sign conventions and standard image-formation conditions should be revised along with the formulas.

Key formulas are:

• Mirror formula: 1/v + 1/u = 1/f

• Lens formula: 1/v − 1/u = 1/f

• Mirror magnification: m = −v/u

• Lens power: P = 1/f

• Prism deviation: δ = i + e − A

• Critical angle: sin θc = smaller refractive index/larger refractive index

• Apparent depth: apparent depth = real depth/μ

Prism and Minimum Deviation

At minimum deviation in a prism:

• i = e

• r1 = r2 = A/2

Concave Mirror

For a concave mirror, an object between the pole and focus forms a virtual, erect and magnified image.

If only a part of a mirror is covered, the complete image is formed with reduced intensity.

It includes practice questions with detailed explanations for revision.

How to Revise Class 12 Physics for NEET 2026?

Class 12 Physics revision becomes more effective when formulas are connected with their applications instead of being memorised in isolation. A revision plan should give attention to formulas, standard graphs, sign conventions, diagrams and repeated NEET-level applications.

1. Focus on Formula Recall Before Problem-Solving

Formula recall before problem-solving is the central strategy for rapid examination revision. Revise the standard equations given in each chapter and then apply them to questions.

2. Revise Sign Conventions and Graphs

Graphs and sign conventions are important parts of Physics revision. Pay attention to the relevant conventions while revising Electrostatics, Optics, circuits and other formula-based topics.

3. Practise Standard Results and Applications

Along with formulas, revise standard results such as resonance conditions, charged-particle motion, capacitor behaviour, minimum deviation and semiconductor biasing.

4. Solve NEET-Level Questions and PYQs

Use question practice to apply the formulas and concepts revised from each chapter. NEET PYQs can help with repeated question patterns and applications.

5. Revise Diagrams and Important Relationships

Diagrams and relationships between quantities should be revised along with formulas. This is particularly useful for topics involving circuits, optics, magnetic fields and semiconductor devices.

6. Prioritise Accurate Attempts

For a difficult Physics paper, attempt easy and familiar questions first, followed by moderate questions, and return to difficult calculations later. Accurate attempts are more valuable than attempting every question.

PW's NEET preparation resources can be used alongside this revision approach for concept revision, question practice and PYQ-based preparation.

For Class 12 Physics revision for NEET 2026, focus on connecting formulas with their physical meaning and applications. Electrostatics, Current Electricity, Capacitors, Magnetism, Electromagnetic Induction and Alternating Current require attention to formulas, conditions and numerical applications. Using PW's NEET preparation resources along with focused question-solving can support revision across these Class 12 Physics topics.

NEET Resources You Might Like: