Complete Physics Formula Revision for NEET 2026 By PW

A strong NEET Physics strategy requires formula recall along with concept clarity. Important results often depend on conditions such as constant acceleration, small oscillations, limiting friction, resonance or total internal reflection. During revision, it is important to understand not only the formula but also the condition under which it can be applied.

This Complete Physics Formula Revision for NEET 2026 by Physics Wallah brings together important formulas and related concepts from across the syllabus. It can help you quickly revisit essential equations, recall their applications and strengthen your formula-based preparation before the exam. 

Units, Dimensions and Measurement

Units and dimensions provide the foundation for checking physical equations and understanding relationships between quantities. Revision should cover SI fundamental quantities, dimensional formulas, unit conversion and the rules for calculating errors.

A physical quantity is written as: Q = numerical value × unit

The product of numerical value and unit remains constant during unit conversion.

The seven SI fundamental quantities are:

• Length: metre

• Mass: kilogram

• Time: second

• Temperature: kelvin

• Electric current: ampere

• Amount of substance: mole

• Luminous intensity: candela

Important Dimensional Results

The principle of homogeneity states that every term in a valid physical equation must have the same dimensions.

For errors:

• Addition and subtraction: add absolute errors.

• Multiplication and division: add fractional or percentage errors.

• Percentage error = fractional error × 100.

Mechanics: Motion, Force and Energy

Mechanics includes equations of motion, circular motion, projectile motion, Newton's laws, work and energy, inclined planes and friction. While revising these formulas, pay attention to the conditions under which they apply, particularly constant acceleration.

For constant acceleration:

• v = u + at

• s = ut + 1/2 at²

• v² = u² + 2as

The equations apply only when acceleration is constant.

Circular Motion

For circular motion:

• Distance along arc = rθ

• Displacement = 2r sin(θ/2)

• Centripetal acceleration = v²/r = rω²

• Linear velocity = rω

• Time period = 2π/ω

Projectile Motion

For projectile motion:

• Range = u² sin 2θ/g

• Maximum height = u² sin²θ/2g

• Time of flight = 2u sin θ/g

• Trajectory: y = x tan θ − gx²/(2u² cos²θ)

The maximum range occurs at 45°. At the highest point, vertical velocity is zero, but horizontal velocity remains u cos θ.

Newton's Laws

Newton's laws give:

• Momentum: p = mv

• Force: F = dp/dt

• Constant-mass form: F = ma

• Impulse: J = change in momentum

Work and Energy

For work and energy:

• Work = F s cos θ

• Kinetic energy = 1/2 mv²

• Gravitational potential energy = mgh

• Spring energy = 1/2 kx²

• Power = work/time

The work-energy theorem is:

Net work done = change in kinetic energy

For an inclined plane without friction:

• Normal reaction = mg cos θ

• Acceleration = g sin θ

Friction

For friction:

• Static friction: 0 ≤ fs ≤ μsN

• Limiting friction: fs,max = μsN

• Kinetic friction: fk = μkN

The angle of repose satisfies: tan θ = μs

Gravitation and Rotational Motion

Gravitation revision should focus on the standard results for gravitational acceleration, escape speed, orbital speed and satellite energy. Rotational motion requires attention to torque, angular momentum, rotational kinetic energy and pure rolling.

At a planet's surface:

• g = GM/R²

• Escape speed = √(2GM/R)

• Orbital speed = √(GM/r)

• Orbital time period = 2π√(r³/GM)

For a satellite in a circular orbit:

• Kinetic energy = GMm/2r

• Potential energy = −GMm/r

• Total energy = −GMm/2r

Kepler's third law: T² ∝ a³

Rotational Motion

For rotational motion:

• Torque = r × F

• Angular momentum = r × p

• Rotational angular momentum = Iω

• Torque = dL/dt

• Rotational kinetic energy = 1/2 Iω²

If external torque is zero: I₁ω₁ = I₂ω₂

For pure rolling: v = Rω

The acceleration of a body rolling down an incline is: a = g sin θ / [1 + k²/R²]

where I = Mk².

Electricity and Magnetism

Electricity and Magnetism include electrostatics, capacitors, current electricity, circuit laws and magnetic fields. Formula revision should be combined with attention to charge, potential, current, resistance and the direction of magnetic forces.

Electrostatics

For electrostatics:

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

• Potential of a point charge: V = kq/r

• Electric flux: Φ = ∮E · dA

• Gauss's law: Φ = Qin/ε₀

• Dipole moment: p = q × separation

• Dipole torque: τ = pE sin θ

• Dipole potential energy: U = −pE cos θ

Capacitors

For capacitors:

• C = Q/V

• Parallel-plate capacitance: C = ε₀A/d

• Capacitor energy: U = 1/2 CV² = Q²/2C = 1/2 QV

• Energy density: u = 1/2 ε₀E²

Series capacitors have equal charge, while parallel capacitors have equal potential difference.

Current Electricity

For current electricity:

• V = IR

• R = ρL/A

• P = VI = I²R = V²/R

• Drift velocity: vd = eEτ/m

• Current: I = neAvd

• Conductivity: σ = ne²τ/m

• Resistivity: ρ = 1/σ

Kirchhoff's Laws

Kirchhoff's laws are:

• Junction law: total current entering = total current leaving.

• Loop law: algebraic sum of potential changes in a closed loop is zero.

For a cell with emf E and internal resistance r:

• Current: I = E/(R + r)

• Terminal voltage while discharging: V = E − Ir

• Maximum power transfer: R = r

Magnetism

For magnetism:

• Long straight wire: B = μ₀I/2πr

• Circular loop centre: B = μ₀I/2r

• Long solenoid: B = μ₀nI

• Force on charge: F = qvB sin θ

• Force on wire: F = BIL sin θ

Parallel currents attract in the same direction and repel in opposite directions.

Electromagnetic Induction and Alternating Current

Electromagnetic Induction and AC involve changing magnetic flux, induced emf, inductance, reactance, impedance and resonance. These formulas should be revised with their respective conditions, especially the resonance condition in an AC circuit.

Faraday's law:

Induced emf = −dΦ/dt

Motional emf: ε = BLv

Self-inductance energy: U = 1/2 LI²

For an AC circuit:

• XL = ωL

• XC = 1/ωC

• RLC impedance: Z = √[R² + (XL − XC)²]

• Average power: P = Vrms Irms cos φ

Resonance in an RLC Circuit

At resonance:

• XL = XC

• Z = R

• Current is maximum

• Resonance frequency: f₀ = 1/(2π√LC)

Optics, Waves and Modern Physics

Optics, Waves and Modern Physics bring together formulas from lenses, mirrors, refraction, YDSE, diffraction, photons, the photoelectric effect, the Bohr model and nuclear physics. Revision should focus on standard equations, sign conventions and the conditions associated with each result.

Lens and Mirror Formulas

For lenses:

• Lens power: P = 1/f

• Lens formula: 1/f = 1/v − 1/u

• Mirror formula: 1/f = 1/v + 1/u

• Mirror magnification: m = −v/u

• Thin-prism deviation: δ = (μ − 1)A

Refraction

For refraction:

• Snell's law: n₁ sin i = n₂ sin r

• Critical angle: sin C = n₂/n₁

• Lateral displacement: s = t sin(i − r)/cos r

Young's Double-Slit Experiment

For YDSE:

• Path difference: Δx = yd/D

• Fringe width: β = λD/d

• Bright fringe: Δx = nλ

• Dark fringe: Δx = (2n − 1)λ/2

For single-slit diffraction, minima occur at: a sin θ = mλ

The central maximum is twice as wide as the other bright regions.

Photons and Photoelectric Effect

For photons:

• E = hν = hc/λ

• Photoelectric equation: hν = φ + Kmax

• Stopping potential: eVs = Kmax

• de Broglie wavelength: λ = h/p

Bohr's Atom

For Bohr's atom:

• Angular momentum: mvr = nh/2π

• Orbit radius: rn = 0.529 n²/Z Å

• Energy: En = −13.6 Z²/n² eV

• Spectral relation: 1/λ = RZ²(1/n₁² − 1/n₂²)

Nuclear Physics

For nuclear physics:

• Nuclear radius: r = r₀A¹ᐟ³

• Binding energy = mass defect × 931.5 MeV

• Alpha decay: A decreases by 4, Z decreases by 2.

• Beta-negative decay: A unchanged, Z increases by 1.

• Beta-positive decay: A unchanged, Z decreases by 1.

• Gamma decay: A and Z remain unchanged.

How to Revise Physics Formulas for NEET 2026?

Formula revision is more useful when each equation is connected with its condition, sign convention, limiting case or physical meaning. Along with revising formulas, practise numerical questions and use previous questions to identify concepts that require further revision.

1. Revise Formulas With Their Conditions

Remember the conditions attached to important formulas. For example, the equations of motion apply only when acceleration is constant.

2. Focus on Units and Dimensions

Use dimensional analysis to check whether the terms in a physical equation have the same dimensions. Also revise SI units and error rules.

3. Pay Attention to Sign Conventions

Sign conventions are particularly important while revising formulas from optics and other chapters where directions and quantities affect the result.

4. Revise Limiting Cases and Standard Results

Keep standard results such as resonance conditions, circular motion relations, projectile results, capacitor combinations and total internal reflection conditions together for quick revision.

5. Practise Numerical Questions

After formula revision, solve numerical questions to apply the relevant equations and identify where formula recall or concept clarity needs improvement.

6. Solve NEET PYQs

Practise NEET PYQs along with formula revision to work through repeated concepts and applications. PW's NEET resources, including PYQs, MCQs, Mind Maps, Sample Papers, Formula resources and YouTube Lectures, can be used as additional support for revision and question practice.

For NEET Physics formula revision, focus on understanding the conditions behind each formula rather than memorising equations in isolation. Units and dimensions, Mechanics, Gravitation, Rotational Motion, Electricity, Magnetism, Electromagnetic Induction, AC, Optics, Waves and Modern Physics each require attention to their important formulas and applications. PW's NEET preparation resources can be used alongside this revision process to support formula recall, concept revision and question practice.

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