Question

The potentials of the two plates of capacitors are $+10\, V$ and $-10\, V$. The charge on one of the plates is $40\, C$. The capacitance of the capacitor is

• A. 2 F
• B. 4 F
• C. 0.5 F
• D. 0.25 F

Answer 1

Answer: (A)

2 F

Answer 2

A capacitor is an arrangement which can store sufficient quantity of charge. Suppose, on given a charge $q$ to a conductor, the electric potential of the conductor becomes $V$. Then, capacitance of capacitor is $C=\frac{q}{V}$ The potential difference across the parallel plate capacitor is $10 V -(-10 V )=20\, V$ $\therefore$ Capacitance $C=\frac{Q}{V}=\frac{40}{20}=2\, F$