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The energy stored in a capacitor of capacitance 10μF carryi...

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 is D

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

1/2 10-3 5.0 x 10-4