How many Physics formulas are there in Class 10?

In the NCERT/CBSE syllabus the formulas sit in two areas: Light (mirror and lens formulas, magnification, refractive index, power of a lens) and Electricity (Ohm's law, resistivity, series and parallel combinations, power and heating). The ICSE syllabus adds force, work and energy, machines, sound and calorimetry.

Which Physics chapter is most important for Class 10 CBSE boards?

In CBSE's 2026-27 course structure, the Effects of Current unit (electricity and magnetic effects) carries 13 marks and Natural Phenomena (light) carries 12, out of 80. Electricity has the most numericals, so master V = IR, P = VI and the series and parallel resistance formulas first.

How do I remember Physics formulas for Class 10?

(1) Write each formula with its meaning and units. (2) Solve a few numericals with it straight away. (3) Keep a one-page formula sheet and review it daily. (4) Understand the derivation where there is one. (5) Group related formulas, such as everything on electric power.

Are these formulas enough for ICSE too?

Not the CBSE section alone. ICSE Class 10 Physics also covers force and moments, work, energy and power, machines, refraction through a prism, sound, emf and internal resistance, calorimetry and radioactivity. The ICSE section on this page lists the formulas for those topics.

Class 10 Physics Formulas — Chapter-Wise

This is the Class 10 Physics formula sheet for the NCERT chapters that CBSE and many state boards follow, followed by the extra formulas ICSE students need. Electricity has the most numericals: master V = IR, P = VI and the resistance formulas first.

Light: Reflection and Refraction

Reflection (Spherical Mirrors)

Formula	Description	Units
1/v + 1/u = 1/f	Mirror formula (derivation not required by CBSE)	v, u, f in cm or m
m = −v/u	Magnification (mirrors)	No unit (ratio)
m = h'/h	Magnification from image and object heights	No unit
f = R/2	Focal length is half the radius of curvature	cm or m

Sign convention (New Cartesian): measure all distances from the pole (or optical centre). Distances in the direction of the incident light are positive, against it negative. With the object on the left, u is always negative.

Refraction (Lenses)

Formula	Description	Units
1/v − 1/u = 1/f	Lens formula (derivation not required by CBSE)	v, u, f in cm or m
m = v/u = h'/h	Magnification (lenses)	No unit
P = 1/f (f in metres)	Power of a lens	Dioptre (D)
n = sin i / sin r	Snell's law	No unit
n = c/v	Refractive index = speed of light in vacuum / speed in the medium	No unit
n₂₁ = n₂/n₁ = v₁/v₂	Refractive index of medium 2 with respect to medium 1	No unit

Remember: a convex lens has positive f and positive power; a concave lens has negative f and negative power.

Electricity

Basic Formulas

Formula	Description	Units
I = Q/t	Current = charge / time	A = C/s
V = W/Q	Potential difference = work done per unit charge	V = J/C
V = IR	Ohm's law	V (volts), I (amperes), R (ohms, Ω)
R = ρL/A	Resistance from resistivity ρ, length L and cross-section area A	ρ in Ω·m

Series and Parallel Combinations

Property	Series	Parallel
Current	Same through each: I = I₁ = I₂ = I₃	Divides: I = I₁ + I₂ + I₃
Voltage	Divides: V = V₁ + V₂ + V₃	Same across each: V = V₁ = V₂ = V₃
Resistance	R = R₁ + R₂ + R₃	1/R = 1/R₁ + 1/R₂ + 1/R₃

Power and Heating

Formula	Description	Units
P = VI = I²R = V²/R	Electric power	Watt (W)
H = I²Rt	Heat produced (Joule's law of heating)	Joule (J)
E = P × t	Electrical energy used	J or kWh
1 kWh = 3.6 × 10⁶ J	One commercial “unit” of electricity	—

Numerical tip: write Given → Formula → Substitution → Answer with units. CBSE marking schemes give marks for correct steps, so a slip in the last line doesn't cost you the whole question.

Practise Physics numericals

Super Tutor has chapter-wise Class 10 Science practice quizzes, including Electricity and Light numericals.

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Magnetic Effects of Electric Current

Rule	What it gives you
Right-hand thumb rule	Thumb along the current; curled fingers give the direction of the magnetic field around the wire
Fleming's left-hand rule	Forefinger = field, middle finger = current, thumb = force on the conductor
Fleming's right-hand rule	Forefinger = field, thumb = motion, middle finger = induced current (used for generators)

This chapter is mostly rules and diagrams, not formulas. In the CBSE 2026-27 syllabus the electric motor, electromagnetic induction and the generator are assessed only by your school, not in the Board exam; alternating current (its frequency and advantages over DC) and domestic circuits are still in the Board syllabus. Sources of Energy is no longer in the CBSE Class 10 syllabus.

ICSE Class 10: Extra Physics Formulas

ICSE Class 10 Physics has chapters that the NCERT books don't. These are their main formulas:

Topic	Formula
Moment of a force	τ = F × d (d = perpendicular distance from the pivot). In equilibrium, sum of clockwise moments = sum of anticlockwise moments.
Work	W = F s cos θ
Power	P = W/t
Kinetic and potential energy	KE = ½mv², PE = mgh; work done = change in kinetic energy
Machines	Mechanical advantage MA = load / effort; velocity ratio VR = distance moved by effort / distance moved by load; efficiency η = MA / VR
Refraction	μ = sin i / sin r = c/v; real depth / apparent depth = μ; critical angle: sin C = 1/μ
Sound	v = fλ; for an echo, distance to the reflector d = vt/2
Cell with internal resistance	ε = V + Ir, so I = ε / (R + r)
Calorimetry	Q = mcΔT; heat capacity = mc; latent heat Q = mL; heat lost by the hot body = heat gained by the cold body
Radioactivity	α emission: mass number −4, atomic number −2. β emission: atomic number +1, mass number unchanged. γ emission: no change in either.

Quick Revision Tips

Print this page or copy the formulas by hand, and review them for 15 minutes every morning.
Solve three numericals after each formula. Reading isn't learning; solving is.
On exam day, jot your key formulas on the rough-work space as soon as writing starts.
Always write units in your answer. A missing unit can cost you marks.
Draw circuit diagrams neatly for Electricity questions.
Draw ray diagrams with a ruler for Light questions and label every point (F, C, P, O, I).

Formulas are from the NCERT Class 10 Science textbook; notes on what is assessed follow the CBSE 2026-27 syllabus. The ICSE section follows the topics in the ICSE Class 10 Physics syllabus. State boards differ, so check your own board's syllabus.

Class 10 Physics Formulas: Chapter-Wise Formula Sheet