Capacitor formulas

Every formula JEE Advanced expects you to know for Capacitor, with the variables spelled out. Free, no sign-up. Read it before a mock, not during one.

Practise these formulas 253 practice questions

Formulas: 32
Subject: Physics
Exam: JEE Advanced
No sign-in needed: ₹0

Capacitor, every formula

32 formulas, typeset and free. Print it, or keep it open beside your practice.

Charge–capacitance relation
$q = C V$
Parallel plate capacitor
$C = \frac{ε _{0} A}{d}$
Capacitor with dielectric
$C = \frac{K ε _{0} A}{d} = K C_{0}$
Isolated spherical conductor
$C = 4 π ε_{0} R$
Spherical capacitor
$C = \frac{4 π ε _{0} ab}{b - a}$
Cylindrical capacitor
$C = \frac{2 π ε _{0} L}{ln ( b / a )}$
Energy stored
$U = \frac{1}{2} C V^{2} = \frac{Q ^{2}}{2 C} = \frac{1}{2} Q V$
Energy density
$u = \frac{1}{2} ε_{0} E^{2}$
Field between plates
$E = \frac{σ}{ε _{0}} = \frac{V}{d}$
Force on a plate
$F = \frac{q ^{2}}{2 A ε _{0}}$
Series combination
$\frac{1}{C _{e q}} = \frac{1}{C _{1}} + \frac{1}{C _{2}} + \dots$
Parallel combination
$C_{e q} = C_{1} + C_{2} + \dots$
n identical in series
$C_{e q} = \frac{C}{n}, V^{'} = \frac{V}{n}$
n identical in parallel
$C_{e q} = n C$
Voltage division (series)
$V_{1} : V_{2} = \frac{1}{C _{1}} : \frac{1}{C _{2}}$
Charge division (parallel)
$Q_{1} : Q_{2} = C_{1} : C_{2}$
Common potential
$V = \frac{C _{1} V _{1} + C _{2} V _{2}}{C _{1} + C _{2}}$
Heat loss on sharing
$Δ U = \frac{1}{2} \frac{C _{1} C _{2}}{C _{1} + C _{2}} (V_{1} - V_{2})^{2}$
Charging: charge
$q = q_{0} (1 - e^{- t / R C})$
Discharging: charge
$q = q_{0} e^{- t / R C}$
Time constant
$τ = R C$
Charging current
$i = \frac{V}{R} e^{- t / R C}$
63% rule (charging)
$t = τ \Rightarrow q = 0.63 q_{0}$
37% rule (discharging)
$t = τ \Rightarrow q = 0.37 q_{0}$
Dielectric constant
$K = \frac{ε}{ε _{0}}$
Bound (induced) charge density
$σ_{b} = σ (1 - \frac{1}{K})$
Field inside dielectric
$E_{in} = \frac{σ}{K ε _{0}} = \frac{E}{K}$
Partially filled dielectric
$C = \frac{ε _{0} A}{d - t + \frac{t}{K}}$
Metal slab inserted
$C = \frac{ε _{0} A}{d - t}$
Battery disconnected (dielectric in)
$Q const, V = \frac{V _{0}}{K}, U = \frac{U _{0}}{K}$
Battery connected (dielectric in)
$V const, Q = K Q_{0}, U = K U_{0}$
Force on dielectric (battery on)
$F = \frac{ε _{0} b ( K - 1 ) V ^{2}}{2 d}$

Know the Capacitor formulas. Now use them.

Formulas only stick when you apply them under time. Adaptive practice picks the concept you keep dropping marks on.

Create a free account All formula sheets

Join QuestPix, Today!

Get notified first, with exam & curriculum updates, course & test series launch offers, motivation & success stories and free learning resources recommended by toppers.

Capacitor formulas

Capacitor, every formula

Charge–capacitance relation

Parallel plate capacitor

Capacitor with dielectric

Isolated spherical conductor

Spherical capacitor

Cylindrical capacitor

Energy stored

Energy density

Field between plates

Force on a plate

Series combination

Parallel combination

n identical in series

n identical in parallel

Voltage division (series)

Charge division (parallel)

Common potential

Heat loss on sharing

Charging: charge

Discharging: charge

Time constant

Charging current

63% rule (charging)

37% rule (discharging)

Dielectric constant

Bound (induced) charge density

Field inside dielectric

Partially filled dielectric

Metal slab inserted

Battery disconnected (dielectric in)

Battery connected (dielectric in)

Force on dielectric (battery on)

More JEE Advanced Physics formula sheets

Know the Capacitor formulas. Now use them.

Join QuestPix, Today!