- A bulb is in series with an inductor of very low resistance. It is connected to a DC supply and glows with normal brightness. It is then connected to an AC supply. Which one of these shows the correct change (if any) that needs to be made to make the bulb glow with normal brightness?
- The voltage of the AC supply needs to be increased.
- The voltage of the AC supply needs to be reduced.
- No change needs to be made to the voltage of the supply.
- The inductor needs to be placed in parallel with the bulb.

- The response of an inductor to an alternating current is called the:
- Inductance;
- Capacitance;
- Reactance;
- Resistance.

- An inductor has 500 turns and when it's disconnected a voltage of 40 V is measured. What is the rate of change of flux with its correct unit?
- 12.5 Wb
- 12.5 Wb s-1
- 0.08 Wb
- 0.08 Wb s-1

- When a current of 8.0 A decays to zero in a time of 12.5 ms, an emf of 90 V is measured. What is the inductance of the inductor?
- 0.9 H
- 0.14 H
- 9.0 H
- 140 H

- An inductor is in series with a resistor. Which one of these is the correct statement about the impedance of the circuit?
- The impedance is the inductance and the resistance added together.
- The impedance is the vector sum inductance and the resistance.
- The impedance is the reactance and the resistance added together.
- The impedance is the vector sum reactance and the resistance.

- A resistor of 150 ohms is in series with an inductor of 0.05 H. Both are connected to a supply that is alternating at 1 kHz. What is the impedance?
- 314 ohms
- 348 ohms
- 464 ohms
- 121000 ohms

- A resistor of 150 ohms is in series with an inductor of 0.05 H. Both are connected to a supply that is alternating at 1 kHz. What is the phase angle in radians?
- 0.48 rad
- 1.12 rad
- 2.09 rad
- 64 rad

- For a loudspeaker in a high fidelity music reproduction system, which one of these statements is correct.
- An inductor is used to filter out high frequencies from the woofer.
- An inductor is used to filter out high frequencies from the tweeter.
- An inductor is used to filter out low frequencies from the tweeter.
- An inductor is used to filter out low frequencies from the woofer.

- A loudspeaker drive unit has an inductance. When it is in series with an inductor that acts as a low pass filter, which of these statements are correct?

1) The low pass filter and loudspeaker have inductances that are modelled as inductors in series;

2) The low pass filter and loudspeaker have resistances that are modelled as resistors in series;

3) The impedance is the arithmetical sum of the impedances of the low pass filter and the loudspeaker;

4) The impedance is the vector sum of the total inductance and the total resistance.

Answer:- If 1, 2 and 3 only are correct.
- If 1 and 2 only are correct.
- If 1, 2, and 4 only are correct.
- If all of them are correct.

- Which one of these statements is NOT true about the skin effect?
- For a DC current, the charge is carried evenly throughout the wire.
- For an AC current, charge carriers are more likely to be found towards the outside surface of the wire.
- Conductors carrying very high frequency AC can be made of hollow tubes.
- The skin depth depends on the current flowing through the conductor.