1.a. Define the insulation resistance. Write down the expression for insulation resistance of the single core cable. State the function on which it depends.

1.b. Two coils, X of 12000 turns. and Y of I5000 turns lie in parallel planes such that 60% of the flux produced by coil X links coil Y. A current of 5A in coil X produces a flux of 0.05 m Wb, while the Same current in coil X produces a flux of 0.075 mWb. Find

i) self inductance of each coil.

ii) mutual inductance.

iii) coefficient of coupling.

2.a. What is magnetic circuit? Fir simple magnetic circuit without air gap obtain the expression for flux.

2.b. A filament lamp has a normal rating of240V, 60W. Ifswitched on at the room temperature of 20°C to the 240V supplys it draws an initial current of2.5A, calculate the temperature of filament in normal hot condition, if the temperature coefficient of resistance at 200C is 0.0055 per °C.

3.a. When two capacitance C1 and C2 are connected in series, derive the equation for total capacitance. Also draw circuit diagram.

3.b. A sinusoidal alternating quantity of 50Hz frequency is having maximum value of 100 Amps. Find time taken ny current to attain

i) 40A form origin and

ii) 70 A after passing through first positive maximum value.

4.a. Write the equation of instantaneous voltage in terms of :

i) Maximum Voltage and coil angle $\theta$

ii) Maximum Voltage and angular velocity

iii) Maximum Voltage and frequency

iv) Maximum Voltage and time period.

Draw the sinusoidal waveform of voltage vs time and show the maximum value, cycle, frequency and periodic time.

4.b. With neat sketches, explain the various types of lamination use for the construction of core of single phase transformer.

5.a. Derive the relationship between the line values and phase values of voltage and current for balanced three phase star connected inductive load with the help of connection diagram and phasor diagram. Hence obtain the total power consumed. Assume phase sequence RYB.

5.b. A R-C series circuit is connected across 100 V, 50 I Hz supply draws a current of 5 A at a powér factor 0.3 leading. Find the value of Rand C. Also find power consumed.

6.a. What is admittance ? Obtain its components and their units. Draw admittance triangle for R-L and R-C circuit.

6.b. b) A coil of inductance 15 mH and resistance 25 S2resistance is connected in series with a capacitor 'C' across 230 y, 50 Hz supply. Find the value of capacitor so that circuit draws maximum current. What will be the power factor and power consumed?

7.a. Elaborate steps to the followed to obtain current through any branch using Thevenin's equivalent circuit.

7.b. Find the current through branch AB using KVL. All resistance are in ohm.

8.a. With usual notation, derive step by step formulae for converting delta elements of the network to star elements on equivalent basis.

8.b. Elaborate steps to be followed to obtain current through any branch using superposition theorem.