Question

A parallel plate capacitor is constructed using two square metal sheets, each of side L = 10 cm. The plates are separated by a distance d = 2 mm and a voltage applied between the plates. The electric field strength within the plates is E = 4000 V/m. The energy stored in the capacitor is

Answer 1

The energy stored is 1.4 x 10^-9 J.

Step-by-step explanation:

Side of square, L = 10 cm = 0.1 m

Distance, d = 2 mm = 0.002 m

Electric field, E = 4000 V/m

The energy stored in the capacitor is

`U = 0.5 C V^2`

The capacitance is given by

`C = (\varepsilon o A)/(d)\\\\So \\\\U = 0.5(\varepsilon o A)/(d)* E^2 d^2\\\\U = 0.5* 8.85* 10^(-12)* 0.1* 0.1* 4000* 4000* 0.002\\\\U = 1.4*10^(-9) J`