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. | \(0\) |
1. | zero | 2. | \(\dfrac{1}{2}\) |
3. | \(\dfrac{1}{\sqrt{2}}\) | 4. | \(1\) |
1. | \(\dfrac{E_{0}^{2}}{R} \sin^{2}\omega t\) | 2. | \(\dfrac{E_{0}^{2}}{R}\cos^{2}\omega t\) |
3. | \(\dfrac{E_{0}^{2}}{R}\) | 4. | \(\text{zero}\) |
In a step-up transformer, the turn ratio is \(1:20\). The resistance of \(100~\Omega\) connected across the secondary is drawing a current of \(2~\text{A}\).
What are the primary voltage and current respectively?
1. \(100~\text{V}, 0.5~\text{A}\)
2. \(200~\text{V},10~\text{A}\)
3. \(10~\text{V}, 40~\text{A}\)
4. \(10~\text{V}, 20~\text{A}\)
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. | \(V_R=V_C \neq V_L\) |
1. | \(20\) W | 2. | \(30\) W |
3. | \(10\) W | 4. | \(40\) W |