A parallel plate capacitor stores 40 mJ of electrostatic energy when connected across a 200 V DC supply. The capacitance of the capacitor is

Question

Quantrex Academy · Accepted Answer

Correct answer: B. 2

The energy stored in a capacitor is given by the formula:

U = \dfrac{1}{2} C V^2

Given:

U = 40 \text{ mJ} = 40 \times 10^{-3} \text{ J}

V = 200 \text{ V}

Substituting the values into the formula:

40 \times 10^{-3} = \dfrac{1}{2} \times C \times (200)^2

40 \times 10^{-3} = \dfrac{1}{2} \times C \times 40000

40 \times 10^{-3} = 20000 \times C

C = \dfrac{40 \times 10^{-3}}{20000}

C = 2 \times 10^{-6} \text{ F}

C = 2 \mu\text{F}

Answer:

2 \mu\text{F}

A parallel plate capacitor stores 40 mJ of electrostatic energy...