In the given circuit, the AC source has ω = 100 rad/s, considering the inductor and capacitor to be ideal,

• the current through the circuit  is 0.4 A

• the current through the circuit is 0.3$\sqrt{2}$ A

• the voltage across 100 Ω  resistor is 10$\sqrt{2}$ V

• the voltage across 50 Ω resistor is 10 V

212.

The impedence of a circuit, when a resistance R and an inductor of inductance L are connected in series in an AC circuit of frequency f, is

• $\sqrt{\mathrm{R} + 2{\mathrm{\pi }}^2 {\mathrm{f}}^2 {\mathrm{L}}^2}$

• $\sqrt{\mathrm{R} + 4{\mathrm{\pi }}^2 {\mathrm{f}}^2 {\mathrm{L}}^2}$

• $\sqrt{{\mathrm{R}}^2 + 4{\mathrm{\pi }}^2 {\mathrm{f}}^2 {\mathrm{L}}^2}$

• $\sqrt{{\mathrm{R}}^2 + 2{\mathrm{\pi }}^2 {\mathrm{f}}^2 {\mathrm{L}}^2}$

In a series LCR circuit, resistance R = 10 Ω and the impedance Z = 10 Ω. The phase difference between the current and the voltage is

• 0°

• 30°

• 45°

• 60°

A circuit consists of an inductance of 0.5 mH and a capacitor of 20 µF. The frequency of the LC oscillations is approximately

• 400 Hz

• 88 Hz

• 1600 Hz

• 2400 Hz

The maximum value of AC voltage in a circuit is 707 V. Its rms value is

• 70.7 V

• 100 V

• 500 V

• 707 V

If an alternating voltage is represented as E = 141 sin (628 t), then the rms value of the voltage and the frequency are respectively

• 141 V, 628 Hz

• 100 V, 50 Hz

• 100 V, 100 Hz

• 141 V, 100 Hz

A step-down transformer is used on a 1000 V line to deliver 20 A at 120 V at the secondary coil. If the efficiency of the transformer is 80%, the current drawn from the line is

• 3 A

• 30 A

• 0.3 A

• 2.4 A

An alternating current of rms value 10 A is passed through a 12 Ω resistor. The maximum potential difference across the resistor is

• 20 V

• 90 V

• 169.68 V

• None of these

In the circuit shown below, the switch is kept in position a for a long time and is then thrown to position b. The amplitude of the resulting oscillating current is given by

• $\mathrm{E}\sqrt{\mathrm{L}/\mathrm{C}}$

• E / R

• infinity

• $\mathrm{E}\sqrt{\mathrm{C}/\mathrm{L}}$