The energy stored in a capacitor of capacitance 10\muF carrying a charge of 100\muC
A
5 x 104 J
B
4 x 102 J
C
4 x 10-3 J
D
5 x 10-4 J
Verified Correct Answer: D.
Physical Principles & Numerical Solution
The energy stored in a given capacitor is given by
E = \(\frac{1}{2}\) CV\(^2\) = \(\frac{1}{2}\) QV = \(\frac{1}{2}\)\(\frac{Q^2}{\text{C}}\)
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 = 10\muF
= 10 x 10\(^{-6}\)F
Q = 100\muc = 100 x 10\(^{-6}\)C
∴ Energy stored = \(\frac{1}{2}\)\(\frac{Q^2}{\text{C}}\)
= \(\frac{1}{2}\)\(\frac{(100 \times 10^{-6})^2}{10 \times 10^{-6}}\)
= 0.0005 = 5 x 10\(^{-4}\)J
Source: Myschool Past Questions Archive (Record #12032)