Question

$700\, pF$ capacitor is charged by $50\, V$ battery. Electrostatic energy is stored by it will be :

• A. $ 17.0\times 10^{-8}J$
• B. $ 13.0\times 10^{-9}J $
• C. $ 8.7\times 10^{-7}J $
• D. $ 6.7\times 10^{-7}J$

Answer 1

Answer: (C)

Here : Capacitance
$C=700\, pF =700 \times 10^{-12} F$
Source voltage $V=50\, V$
Electrostatic energy is given by
$E =\frac{1}{2} C V^{2}$
$=0.5 \times 700 \times 10^{-12} \times(50)^{2}$
$=8.7 \times 10^{-7} J$