A circuit having a self inductance of 1 henry carries a current of 1 A . To prevent the sparking when the circuit is broken, a capacitor which can withstand 500 V is connected across the switch. What is the minimum value of the capacitance of the capacitor?

Step-by-step solution

The energy stored in the inductance is U = 1 2 LI ^2 U = 1 2 1 1^2=0.5 ~J This energy must be transferred to the capacitor. Energy stored by a capacitor U = 1 2 CV ^2 array ll & 1 2 C V^2= 1 2 L I^2 & C=L ( I V )^2=1 ( 1 500 )^2=4 F array