Q. No.An AC voltage source is connected to a series \(LCR\) circuit. When \(L\) is removed from the circuit, the phase difference between current and voltage is \(\dfrac{\pi}{3}\). If \(C\) is instead removed from the circuit, the phase difference is again \(\dfrac{\pi}{3}\) between current and voltage. The power factor of the circuit is:
1. \(0.5\)
2. \(1.0\)
3. \(-1.0\)
4. zero
1. \(0.5\)
2. \(1.0\)
3. \(-1.0\)
4. zero
| 1. | \(2\) A | 2. | \(18\) A |
| 3. | \(12\) A | 4. | \(1\) A |
| 1. | \(484~\text{W}\) | 2. | \(848~\text{W}\) |
| 3. | \(400~\text{W}\) | 4. | \(786~\text{W}\) |
| 1. | \(1.0~\text{A}\) | 2. | \(15~\text{A}\) |
| 3. | \(15.92~\text{A}\) | 4. | \(14.29~\text{A}\) |
1. \(35\)
2. \(20\)
3. \(15\)
4. \(25\)
The variation of EMF with time for four types of generators is shown in the figures. Which amongst them can be called AC voltage?
 |
 |
| (a) | (b) |
 |
 |
| (c) | (d) |
| 1. | (a) and (d) |
| 2. | (a), (b), (c), and (d) |
| 3. | (a) and (b) |
| 4. | only (a) |
| 1. | \(50\) V | 2. | \(50 \sqrt{2} ~\text{V}\) |
| 3. | \(100\) V | 4. | \(0\) V |
A transistor-oscillator using a resonant circuit with an inductance \(L\) (of negligible resistance) and a capacitance \(C\) has a frequency \(f\). If \(L\) is doubled and \(C\) is changed to \(4C\), the frequency will be:
1. \(\frac{f}{4}\)
2. \(8f\)
3. \(\frac{f}{2\sqrt{2}}\)
4. \(\frac{f}{2}\)
An ideal resistance \(R\), ideal inductance \(L\), ideal capacitance \(C\), and AC voltmeters \(V_1, V_2, V_3~\text{and}~V_4 \)
| 1. | Reading in \(V_3\) = Reading in \(V_1\) |
| 2. | Reading in \(V_1\) = Reading in \(V_2\) |
| 3. | Reading in \(V_2\) = Reading in \(V_4\) |
| 4. | Reading in \(V_2\) = Reading in \(V_3\) |
For which of the following reasons are LC oscillations not sustainable for long?
| 1. | Every inductor has some resistance. |
| 2. | The effect of resistance is to introduce a damping effect on the charge & current in the circuit and the oscillations finally die away. |
| 3. | Even if the resistance is zero, the total energy of the system is radiated away from the system in the form of electromagnetic radiation. |
| 4. | All of the above |
© 2024 GoodEd Technologies Pvt. Ltd.