The charge on capacitor of capacitance 15μF in the figure given below is :

Solution

Physics sir · 4 steps

All three capacitors sit in one loop, so they are in series and carry the same charge.

1. Spot the series. The 10, 15 and 20 μF capacitors lie one after another in a single loop with the 13 V source. There is no branch, so they are in series and every one holds the same charge Q.

   1/C_(eq) = 1/10 + 1/15 + 1/20 = (6 + 4 + 3)/60 = 13/60

2. Equivalent capacitance. So C_(eq) = 60/13 μF.
3. Charge from source. Q = C_(eq) V = 60/13 × 13 = 60 μC.
4. So. The charge on the 15 μF capacitor is the same series charge, 60 μC, option (a).

The idea to keep. In series, find the charge once using the equivalent capacitance. That same charge sits on every capacitor. Only the voltage across each one is different.

Answer from the NTA final answer key. Solution by PrepWiser.