A series RC circuit has R = 5 Ω and C = 10 μF. The current in the circuit is 5 sin 20000t. The applied voltage is

• 252 sin (20000t + 45°)
• 252 sin (20000t - 45°)
• 252 sin 20000t
• 252 sin (20000t - 90°)

Correct Answer: 252 sin (20000t - 45°)

Explanation:

Z = R² + X_C² = 50

V = 550 sin(20000 t - 45°)

V = 252 sin(20000 t - 45°)