A certain capacitor stores 473 J of energy when it holds 7.91 x 10−2 C of charge. What is the capacitance of this capacitor?

Question

What is the potential difference across the plates?

Answer 1

Energy = 0.5C*V^2 = 473 J.
C = Q/V,
Substitute Q/V for C:
0.5(Q/V)*V^2 = 473,
0.5QV = 473,

V=473 / 0.5Q=946 / Q=946 / .0791=11960
volts.

C = Q/V = 0.0791 / 11960 = 6.6*10^-6 F.
= 6.6 uF.