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APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
FIRST SEMESTER B.TECH DEGREE EXAMINATION, DECEMBER 2018
= Course Code: BE101-03 ∙
Course Name: INTRODUCTION TO ELECTRICAL ENGINEERING
Max. Marks: 100 Duration: 3 Hours
PART A
Answer all questions, each carries 4 marks. Marks

1 Define self inductance of a coil. Derive an expression for the self inductance. (4)

2 State and explain Kirchhoff’s voltage and current laws. (4)

3 Draw series and parallel magnetic circuits and show their electrical equivalents. (4)

4 A magnet of square cross-section with a side of 5 cm has a magnetic flux of 0.5 (4)
mWb. Calculate magnetic flux density.

5 An alternating current is given by i=62.35 sin(323t) A. Find its frequency and (4)
form factor.

6 Find the peak factor of a sinusoidal wave. (4)
What is resonant frequency? Why parallel resonance is called current (4)
resonance?

8 Explain the terms real, reactive and apparent powers. (4)
Compare star and delta connection of three phase circuits. (4)

10 Two watt meters are connected to measure power in a 3 phase circuit. One of (4)
the wattmeters reads 500 W and the other points in the reverse direction. After
reversing the voltage coil terminals, the reading of this wattmeter is found to be
200 W. Determine the power factor of the load and total power of the circuit.

PART B
Answer any four full questions, each carries 10 marks.
11 9) List the factors on which the reluctance of a magnetic material depends. (2)
0) A coil consists of 1000 turns of wire uniformly wound on 8 non-magnetic ring (8)
of mean diameter 25 cm and cross sectional area 10cm’. Calculate
(i) The inductance of the coil
(ii) = Energy stored in the magnetic field when the coil is carrying ۸
current, and
(111) Emf induced in the coil if this current is completely interrupted in
0.01s.
12 For the circuit shown, find voltage across the 10 Q resistor using i) Nodal (10)

analysis and _ ii) Mesh analysis

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