A series LCR circuit with \(R=20\Omega \) , L = 1.5H and \(C=35\mu F\) is connected to a variable frequency 200 V ac supply. When the frequency of the supply equals the natural frequency of the circuit, what is the average power transferred to the circuit in one complete cycle?

3

(a)

A coil of inductance 0.50H and resistance \(100\Omega \) is connected to a 240V, 50 Hz AC supply. 
(a) What is the maximum current in the coil?
(b) What is the time lag between the voltage maximum and the current maximum?

3

(a)

A \(100\mu F\) capacitor in series with a \(40\Omega \) is connected to a 110 V, 60 Hz supply.
(a) What is the maximum current in the circuit?
(b) What is the time lag between the current maximum and the voltage maximum?

3

(a)

Explain why the coils of the resistance box are wound over themselves.

3

(a)

Define the term self inductance. Write two factors on which the self inductance of a coil depends.

3

(a)

What is an ideal inductor?

3

(a)

Predict the direction of induced current in the situations described by the following Fig.

3

(a)

A 100 resistor is connected to a 220V, 50Hz ac supply.
(a) What is the rms value of current in the circuit?
(b) What is the net power consumed over a full cycle?

3

(a)

A 60\(\mu\)F capacitor is connected to a 110V, 60Hz a.c.supply. Determine the r.m.s. value of current in the circuit.

3

(a)

Obtain the resonant frequency \(\left( { \omega }_{ r } \right) \) of a series LCR circuit with L=2.0H, C = 32\(\mu\)F and R=10 ohm. What is the Q value of this circuit?

3

(a)

A charged 30\(\mu \)F capacitor is connected to a 27mH inductor. What is the angular frequency of free oscillations of the circuit?

3

(a)

Define the term self-inductance of a solenoid. Obtain the expression for the magnetic energy stored in an inductor of self-inductance L to build up a current I through it.

3

(a)