What is meant by E.M.F. of a source Distinguish between ideal and practical voltage sources.
Discuss critically the active, reactive and apparent power in a single phase A.C. circuit and their relations.

2.(a) Explain the construction and working of a lead acid storage battery.
Explain the charging method used for a lead acid battery.

3.(a) What are the important features of network theorems State Thevenin's theorem.
State Norton's theorem. Determine the voltage across 200 Q resistance in the following network by using Norton's theorem: <img src='./qimages/11531-3b.jpg'>
4.(a) Derive an expression for the field strength at the centre of a long solenoid of turns having a length of metres and carrying a current amperes. A cast steel electromagnet has an air gap length of 3 mm and an iron path at length 40 cm. Find the number of ampere turns necessary to produce a flux density of 0·7 Wb/m^2 in the gap. Neglect leakage and fringing. Assume flux density in gap =flux density in iron portion =0·7 Wb/m^2 .

5.(a) Derive the relationship between the voltage and current for a purely inductive circuit. Also show that the average power consumed by the above circuit is zero.
Draw the phasor diagrams for the following:
Purely resistive circuit

(ii) R-L circuit

(iii) R-C circuit
circuit

6.(a) Explain why the series resonant circuit is often regarded as the. acceptor circuit and the parallel circuit as the rejector circuit.
A coil of resistance 20 ohm and inductance 0·2 H is connected in series with a condenser of capacitance 200 uF across a 250 50 Hz supply. Determine the impedance, current, and power factor.

7. Write short notes on any two of the following:
Superposition Theorem r.m.s. value and average value of A.C. sinusoidal current Energy stored in a magnetic field Force between two parallel current carrying conductors