11The electrostatic potential energy in a capacitor is stored in the electric field b/w the plates of the capacitor, with energy density (energy per ubit volume) u = (1/2) e0 E2
Since Electric field near a charged conductiong surface is given by E= sigma / e0
Therefore, E = 10 -4 / e0
Therefore u = (1/2) e0 (10 -4 / e0 )2
= (1/2) (10 -8) / e 0
Since a = 1cm = 10 -2 m
Therefore, electrostatic P.E , U = u (a 3)
= (1/2) (10 -8) / e 0 (10 - 8)
=5.65 × 10–4 J
