1 (a)
Explain effect of temperature on resistance

3 M

1 (b)
Derive equivalent resistances for delta to star transformation.

6 M

1 (c)
A 100 V, 100 W lamp is connected in series with a A 100 V, 60 W lamp across 200 V supply. Determine current drawn and power consumed by each lamp.

5 M

2 (a)
Draw wiring diagram for staircase wiring.

3 M

2 (b)
Derive expression for voltage across capacitor (v

_{c}) during charging of capacitor.
6 M

2 (c)
Three capacitors having capacitances of 10 μF, 20 μF and 40μF are connected in series to a 400 V d.c. source. Find (i) total capacitance (ii) total charge in circuit (iii) total energy stored.

5 M

3 (a)
State similarities between magnetic circuit and electrical circuit

4 M

3 (b)
Explain self induced emf and mutually induced emf.

6 M

3 (c)
An iron ring has mean diameter of 57.3 cm. It carries a coil having 450 turns and the current flowing through coil is 2 A. The relative permeability of the iron is 1200. Calculate the flux density produced.

4 M

4 (a)
Define : (i) Frequency (ii) Average value (iii) power factor.

3 M

4 (b)
Prove that current in pure inductive circuit lags its voltage by 90°

6 M

4 (c)
Two currents are given by expression: i

_{1}=40 sin(314t+30°) and i_{2}=20 sin(314t-60°). Find expression for (i_{1}- i_{2}).
5 M

5 (a)
Explain series resonance circuit. Draw resonance curve.

7 M

5 (b)
A coil resistance 15Ω and inductance 0.05 H is connected in parallel with a non-inductive resistance of 20Ω. The circuit is connected across 200 V, 50 Hz supply. Determine (i) current in each branch (ii) total current supplied (ii) power factor of the combination.

7 M

6 (a)
Establish relation between line voltage & phase voltage and current relation in 3-phase star connection. Draw phasor diagram.

7 M

6 (b)
Explain two wattmeter method for 3-phase power measurement

7 M

7 (a)
State types of fuse and explain any one.

4 M

7 (b)
Explain different types of lighting schemes.

5 M

7 (c)
Explain construction of cable.

5 M

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