A flat capacitor with a capacity of 50pF is charged with a charge of 2 * 10 ^ -5kl.

A flat capacitor with a capacity of 50pF is charged with a charge of 2 * 10 ^ -5kl. What is the energy of the capacitor’s electric field?

C = 50 pF = 50 * 10 ^ -12 F.
q = 2 * 10 ^ -5 Cl.
W -?
The formula for determining the energy of the electric field W of a flat capacitor is: W = q ^ 2/2 * C.
Where q is the charge on the capacitor plates, C is the capacitance of the capacitor.
W = (2 * 10 ^ -5 C) ^ 2/2 * 50 * 10 ^ -12 F = 4 * 10 ^ -10 / 100 * 10 ^ -12 = 4 J.
Answer: the energy of the electric field of a charged flat capacitor W = 4 J.