2026 Electrostatic Potential and CapacitanceEnergy loss on sharing charge between two capacitors Medium Question 2 of 76 in Electrostatic Potential and Capacitance

Consider two uncharged capacitors of equal capacitance 200 pF. One of them is charged by a 100 V supply and disconnected. Now this capacitor is connected to the uncharged capacitor. The amount of electrostatic energy lost in the process is:

A $1.0 \times 10^{-6}$ J
B $0.5 \times 10^{-6}$ J
C 0.5 J
D 1.0 J

The answer is B.

Solution

Heat loss $\Delta H = \frac{1}{2}\frac{C_1 C_2}{C_1 + C_2}(V_1 - V_2)^2$ $= \frac{1}{2}\left(\frac{200 \times 200}{200 + 200}\right)(100 - 0)^2 \times 10^{-12}$ J $= 50 \times 10^4 \times 10^{-12}$ J $= 5 \times 10^{-7}$ J $= 0.5 \times 10^{-6}$ J

Electrostatic Potential and Capacitance in past papers

76 questions from this chapter have appeared across 27 exam years.