When a step-down transformer is connected to a 2400 volt line, the output load receives 80 amps of current. The ratio of the turns in the primary and secondary coils is 20:1. If transformer efficiency is 100%, then the current flowing in the primary coil will be:

1.	1600 A	2.	20 A
3.	4 A	4.	1.5 A

A generator produces a voltage that is given by V = 240 sin 120 t, where t is in seconds. The frequency and r.m.s. voltage are:

In an ac circuit, the current is given by \(i=5\sin(100t-\frac{\pi}{2})\) and the ac potential is V = 200 sin(100t) volt. The power consumption is:

1. 20 W

2. 40 W

3. 1000 W

4. 0 

In an LCR circuit having L = 8.0 henry, C = 0.5 μF and R = 100 ohm in series, what is the resonance frequency?

1. 600 radian/sec

2. 600 Hz

3. 500 radian/sec

4. 500 Hz

A circuit consists of 3 ohms of resistance and 4 ohms of reactance. The power factor of the circuit is:

1. 0.4

2. 0.6

3. 0.8

4. 1.0

The power factor of a good choke coil is:

1. Nearly zero

2. Exactly zero

3. Nearly one

4. Exactly one

In a series LCR circuit, resistance \(R=10~\Omega\) and the impedance \(Z=20~\Omega\). The phase difference between the current and the voltage will be:

1. 30°

2. 45°

3. 60°

4. 90°

In the circuit shown in the figure, neglecting source resistance, the voltmeter and ammeter reading respectively will be:

1. 0 V, 3 A
2. 150 V, 3 A
3. 150 V, 6 A
4. 0 V, 8 A

An ac source of variable frequency f is connected to an LCR series circuit. Which of the following graphs represents the variation of the current I in the circuit with frequency f?

1.		2.
3.		4.

An inductor of \(20~\mathrm{mH},\) a capacitor of \(50~ \mu F,\) and a resistor of \(40~ \Omega\) are connected in series across a source of emf of \(V=10sin(340t).\) What will be the power loss in the AC circuit?