Question

The plates of a parallel plate capacitor have an area of 100cm^2 each & are separated by 3mm. The capacitor is charged by connecting it to a 400V supply.
a) Calculate the electrostatic energy stored in the capacitor
b) If a dielectric of dielectric constant 2.5 is introduced between the plates of the capacitor, then find the dectrostatic energy stored and also change in the energy stored.​

Answer 1

Answer:

Given A = 100 cm2 = 100 x 10–4m2,

d = 3 mm = 3 x 10–3m, V = 400 V, U1 = ?

K = 2.5, U2 = ? also U2 – U1 = ?

U =

1

2

C

V

2

12CV2 C =

ε

0

A

d

ε0Ad

Calculating

U1 = 23.608 x 10–7J

U2 = 59.02 x 10–7J

U2 ∼ U1 = 35.412 x 10–7J