The primary winding of a transformer has 500 turns whereas its secondary has 5000 turns. The primary is connected to an ac supply of 20 V, 50 Hz. What will be the output of the secondary transformer?
1. | 200 V, 50 Hz |
2. | 2 V, 50 Hz |
3. | 200 V, 500 Hz |
4. | 2 V, 5 Hz |
If R and L are resistance and inductance of a choke coil and f is the frequency of current through it, then the average power of the choke coil is proportional to:
1. \(R ~\)
2. \(\frac{1}{f^2}\)
3. \(\frac{1}{L^2}\)
4. All of these
1. | Zero | 2. | 100 V |
3. | 200 V | 4. | 500 V |
The power factor of the given circuit is:
1. | \(1 \over 2\) | 2. | \(1 \over \sqrt2\) |
3. | \(\sqrt3 \over 2\) | 4. | \(0\) |
The power factor of a series LCR circuit in resonance condition is:
What is the instantaneous power of a resistor having resistance R across an ac supply of E=E0sin ωt?
In a step-up transformer, the turn ratio is 1: 20. The resistance of 100 connected across the secondary is drawing a current of 2 A. What are the primary voltage and current respectively?
1. 100 V, 0.5 A
2. 200 V, 10 A
3. 10 V, 40 A
4. 10 v, 20 A
1. | The voltage leads the current by \(30^{\circ}\). |
2. | The current leads the voltage by \(30^{\circ}\). |
3. | The current leads the voltage by \(60^{\circ}\). |
4. | The voltage leads the current by \(60^{\circ}\). |
1. | \(10~\text{mA}\) | 2. | \(20~\text{mA}\) |
3. | \(40~\text{mA}\) | 4. | \(80~\text{mA}\) |
1. | \(V_r=V_L>V_C\) |
2. | \(V_R \neq V_L=V_C\) |
3. | \(V_R \neq V_L \neq V_C\) |
4. | \(V_R=V_C \neq V_L\) |