A 600 pF capacitor is charged by a 200 V supply. It is disconnected from the supply and connected to another uncharged 600 pF capacitor. Find the electrostatic energy lost in the process, in µJ.
Physics · Capacitor
JEE Advanced

Question

A 600 pF capacitor is charged by a 200 V supply. It is disconnected from the supply and connected to another uncharged 600 pF capacitor. Find the electrostatic energy lost in the process, in µJ.

G1 Physics · Accepted Answer

Initially Uᵢ = ½CV². After connecting an identical uncharged capacitor, the common voltage is V/2, so U𝒇 = 2·½C(V/2)² = ¼CV². Therefore energy lost = ¼CV² = 6 µJ.