An RC series circuit with R = 150 Ω and C = 2 μF is excited by a DC source of 15 V by closing the switch at t = 0 with an initially uncharged capacitor. The initial and final voltages across the capacitor respectively are

• A. 15 V, 10 V
• B. 0 V, 10 V
• C. 10 V, 15 V
• D. 0 V, 15 V

Answer: (D)

For t = 0 in RC circuit,
After t = 0+ condition, capacitor is behave as short circuit.
Voltage across the it 0.
At final time,
Capacitor is behave as open circuit, voltage across the capacitor at final time is equal to 15 V.

Capacitor opposes the change of voltage.