A 15-μF capacitor is charged to 40 V and then connected across an initially uncharged 25-μF capacitor. What is the final potential difference across the 25-μF capacitor?
A) 12 V
B) 18 V
C) 15 V
D) 21 V
E) 24 V

Question

Quizplus · Accepted Answer

When two capacitors are connected in parallel, the total charge is conserved, and they share the same potential difference. The initial charge on the 15-μF capacitor is $Q = CV = 15\mu F \times 40V = 600\mu C$. When this charge is distributed between the 15-μF and 25-μF capacitors, the total capacitance becomes $15\mu F + 25\mu F = 40\mu F$. The final voltage across both capacitors is given by $V = \frac{Q}{C} = \frac{600\mu C}{40\mu F} = 15V$.

A 15-μF Capacitor Is Charged to 40 V and Then