1. | resonance in AC circuits |
2. | logic gate |
3. | x-rays |
4. | none of the above |
In the free oscillations of an LC circuit, the sum of energies stored in the capacitor and the inductor is:
1. | maybe constant and variable in time |
2. | variable in time |
3. | constant in time |
4. | none of the above |
A condenser of capacity C is charged to a potential difference of V1. The plates of the condenser are then connected to an ideal inductor of inductance L. The current through the inductor, when the potential difference across the condenser reduces to V2 is:
1.
2.
3.
4.
To reduce the resonant frequency in an LCR series circuit with a generator:
1. | the generator frequency should be reduced |
2. | another capacitor should be added in parallel to the first |
3. | the iron core of the inductor should be removed |
4. | the dielectric in the capacitor should be removed |
An LC circuit contains a 20 mH inductor and a 50 µF capacitor with an initial charge of 10 mC. The resistance of the circuit is negligible. Let the instant the circuit is closed be t = 0. What is the total energy stored initially?
1. 1.0 J
2. 2.0 J
3. 2.2 J
4. 3.3 J
A charged 30 µF capacitor is connected to a 27 mH inductor. What is the angular frequency of free oscillations of the circuit?
1. \(1.11 \times 10^{3} \ rad/s\)
2.\(2.11 \times 10^{3} \ rad/s\)
3.\(1.11 \times 10^{2} \ rad/s\)
4.\(1.11 \times 10^{4} \ rad/s\)
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 |
In which of the following circuits can the power factor be zero?
1. LC circuit
2. LCR circuit
3. Purely resistive circuit
4. Both (1) & (2)
An LC circuit contains an inductor (L=25 mH) and a capacitor (C=25 mF) with an initial charge of Q0. At what time will the circuit have an equal amount of electrical and magnetic energy?
4. All of these