In a step-up transformer, the turn ratio is 1:2 . A Leclanche cell (e.m.f. 1.5 V) is connected across the primary coil. What would be the voltage developed in the secondary coil?
1. | 3.0 V | 2. | 0.75 V |
3. | 1.5 V | 4. | Zero |
A 220 V, 50 Hz ac source is connected to an inductance of 0.2 H and a resistance of 20 ohms in series. How much current flows across the circuit?
1. 10 A
2. 5 A
3. 33.3 A
4. 3.33 A
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 |
1. | \(60\) Hz and \(240\) V |
2. | \(19\) Hz and \(120\) V |
3. | \(19\) Hz and \(170\) V |
4. | \(754\) Hz and \(70\) V |
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 \(L = 8.0~\text{H}\), \(C= 0.5~\mu\text{F}\) and \(R = 100~\Omega\) 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. \(30^{\circ}\)
2. \(45^{\circ}\)
3. \(60^{\circ}\)
4. \(90^{\circ}\)