Question

A 100 μF capacitor in series with a 40 Ω resistance is connected to a 110 V, 60 Hz supply.

(a) What is the maximum current in the circuit?

(b) What is the time lag between the current maximum and the voltage maximum?

Answer 1

Capacitance of the capacitor, C = 100 μF = 100 × 10⁻⁶ F

Resistance of the resistor, R = 40 Ω

Supply voltage, V = 110 V

(a) Frequency of oscillations, ν= 60 Hz

Angular frequency,

For a RC circuit, we have the relation for impedance as:

Peak voltage, V₀ =

Maximum current is given as:

(b) In a capacitor circuit, the voltage lags behind the current by a phase angle ofΦ. This angle is given by the relation:

Hence, the time lag between maximum current and maximum voltage is 1.55 ms.