The energy stored in a capacitor of capacitance 10μF carrying a charge of 100μC?

A. 5 x 10⁴ J
B. 4 x 10² J
C. 4 x 10^-3 J
D. 5 x 10^-4 J

Correct Answer:

Option D = 5 x 10^-4 J

Explanation

The energy stored in a given capacitor is given by
E = ¹/₂ CV² = ¹/₂ QV = ¹/₂Q²/C
Where C = the capacitance of the capacitor
Q = charge carried by the capacitor
V = p.d across the plates of the capacitor thus from the data given, C = 10μF
= 10 x 10^-6F
Q = 100μc = 100 x 10^-6C
∴ Energy stored = ¹/₂ Q²/C

=	1	(100 x 10-6)2 10 x 10-6
	2

 

=	1	100 x 10-12 10 x 10-6
	2

5.0 x 10^-4