Question Paper: Basic Electrical Engineering (BEE) : Question Paper Dec 2013 - First Year Engineering (Semester 2) | Pune University (PU)
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## Basic Electrical Engineering (BEE) - Dec 2013

### First Year Engineering (Semester 2)

TOTAL MARKS: 50
TOTAL TIME: 2 HOURS
(1) Solve Q.1 or Q.2, Q.3 or Q.4, Q.5 or Q.6, Q.7 or Q.8
(2) Assume suitable data, if necessary.

### Answer any one question from Q1 & Q2

1 (a) Define Insulation Resistance and derive expression for it of a Cable.(6 marks) 1 (b) A single core cable has its conductor diameter as 2 cm and outer diameter as 5 cm. The resistivity of conductor and insulator are 1.73 × 10-8 ? -m and 8×1012? -m respectively. Calculate resistance of conductor and insulation for a cable of 100 meter.(6 marks) 2 (a) Derive an expression for Energy stored in a magnetic field.(6 marks) 2 (b) An iron ring of mean circum ference of 50 cm has an airgap of 2mm cut in it. It has circular cross section with area of 5 cm2. It carries a coil wound with 600 turns wound uniformly. The relative permeability of iron is 580. If the coil carries a current of 2 amp. Find the Flux in air gap.(6 marks)

### Answer any one question from Q3 & Q4

3 (a) Derive an expression of Average value of an alternating simusoidal current.(6 marks) 3 (b) An inductive coil, having negligible resistance and 0.1 H inductance, is connected across a 200V, 50Hz supply. Find
(i) Inductive reactance.
(ii) RMS value of current drawn. State equations for voltage & current.
(6 marks)
4 (a) Compare core type and shell type transformer construction.(6 marks) 4 (b) A 25k VA, 2200/20V 50Hz single phase transformer has a primary resistance of 1.8 ? and secondary resistance of 0.02 ?. Calculate the transformer efficiency at half load 0.8 lagging p.f. The Iron Losses are 1000 watt.(6 marks)

### Answer any one question from Q5 & Q6

5 (a) A circuit, consisting of resistance of 20 ? and inductance of 0.1 H in series, is connected across single phase 220V, 50Hz supply.
Calculate :
(1) Current drawn
(2) p.f. and
(3) Power consumed by ckt.
(7 marks)
5 (b) Define:
(1) Impedance and