Question: Elements of Electrical Engineering : Dec 2014 - First Year Engineering (Semester 1) | Gujarat Technological University (GTU)
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## Elements of Electrical Engineering - Dec 2014

### First Year Engineering (Semester 1)

TOTAL MARKS: 100
TOTAL TIME: 3 HOURS
(1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks.

1 (a) 1 The electrical force or pressure that causes the electrons to move in a particular direction is called as the __________________.
(A) Magneto motive force (
B) Electromotive force (
C) Electrostatic force (
D) Electromagnetic force
(1 marks)
1 (a) 2 The charge on each electron is _____________ coulomb.
(A) 1.9 × 10-19 (
B) 1.6 × 10-19 (
C) 1.9 × 10-16 (
D) 1.6× 10-16
(1 marks)
1 (a) 3 The unit of resistivity is ____________________
(A)Ω (
B) Ω-m (
C) m/Ω (
D) Ω-m -1
(1 marks)
1 (a) 4 Coulomb's Second Law is called as _______________ law.
(A) Inverse square (
B) Charge (
C) Induction
(1 marks)
1 (a) 5 The magnetic lines of force are known as lines of ___________________
(A) magnetic flux (
B) Electromagnetism (
C) Magnetic field
(1 marks)
1 (a) 6 Magnetic flux density is measured in _____________
(A) wb (
B) m2 /wb (
C) wb/m2 (
D) Tesla/m2
(1 marks)
1 (a) 7 The correct relation between the three permeability is ________________
(A) μ=μ0 μ (
B) μ0=μ μr (
C) μ=μ0 μr (
D) μ=μ/μ0
(1 marks)

1 (b) 1 Multimeter can be used to measure
(a) current (b) voltage (c) resistance (d) all of the above
(1 marks)
1 (b) 2 Measuring range of voltmeter can be extended by using
(a) high shunt resistance (b) high series resistance (c) low shunt resistance (d)low series resistance
(1 marks)
1 (b) 3 Full name of ELCB is
(a) Earth leakage circuit breaker (b) Earth less circuit breaker (c ) Earth loser circuit breaker
(d)Earth leakage circuit broker
(1 marks)
1 (b) 4 Ammeter always connected is ________ in a circuit.
(a) Parallel (b) series (c) both (a) & (b)
(d)none of the above
(1 marks)
1 (b) 5 Which of the following insulation is used in cables?
(a) Rubber (b) Paper (c) Porcelain (d) any of the above
(1 marks)
1 (b) 6 Blinking of a fluorescent tube may be due to
(a) low circuit voltage (b) low ballast rating (c) low temperature (d) any of the above
(1 marks)
1 (b) 7 The LED is usually made of materials like
(a) GaAs (b) C and Si (c) GeAs (d) None of the above
(1 marks)
1 (c) 1 An alternating quantity is defined as the one which changes its _____________ as well as__________ with respect to time.
A) Value, direction (
B) Phase, polarity (
C) Value, phase
(1 marks)
1 (c) 2 The AC voltage generators are called as ______________
(A) Alternator (
B) Induction generators (
C) alternating generator
(1 marks)
1 (c) 3 The maximum value of an AC quantity is called as its ________________
(A) Amplitude (
B) Peak to peak value (
C) RMS value
(1 marks)
1 (c) 4 RMS value is also called as __________________ of AC current
(A) Light producing component (
B) heat producing component (
C) Useful component (
D) Useless component
(1 marks)
1 (c) 5 Peak value of sinusoidal waveform is equal to __________________
(A) 0.637 × Vaverage (
B) 0.637 Vrms (
C) 0.707 Vrms (
D) 1.414 Vrms
(1 marks)
1 (c) 6 Filament material used in fluorescent tube is made up of_________________
(A) Nicron (
B) copper (
C) tungsten (
D) aluminium
(1 marks)
1 (c) 7 Complete the following formula: 1 radian =_________________degrees
(A) π/180 (
B) 180/π (
C) π/360 (
D) 360/π
(1 marks)
2 (a) State and explain Kirchhoff's laws.(3 marks) 2 (b) Derive and obtain the expression for temperature co efficient of resistance.
α2=1/(1/α1+(t2-t1))
(4 marks)
2 (c) The resistance of a coil embedded in a large transformer is 12 Ω at 25°C after the transformer has been in operation for several hours, the resister of the coil found to be 13.4Ω. Find the Temperature the transformer core. Take α20 = 0.00393°C-1(7 marks) 3 (a) Compare series and parallel resonance.(3 marks) 3 (b) Compare the following term with respect to AC waveform.
(1)Power factor (2) Average value (3) R.M.S value (4) Form factor
(4 marks)
3 (c) A Series RLC circuit consists of resistance of 500 ?, inductance of 50mHand a capacitance Of 20pF.
Find
(1) the resonant frequency
(2) The Q factor of the circuit of resonance
(3) The half power frequency
(7 marks)
4 (a) State Coulomb's law of electrostatics(3 marks) 4 (b) Give similarities and dissimilarities between electrical circuit and magnetic circuit.(4 marks) 4 (c) Obtain the relation L=(L1L2-M2) / (L1+L2+M2) for equivalent inductance when two inductors are connected in parallel such that the mutual induced emf opposes the self induced emf.(7 marks) 5 (a) Explain magnetic hysteresis.(3 marks) 5 (b) State and explain Faraday's law of electromagnetic induction(4 marks) 5 (c) Find resistance between terminals AB of network shown in figure. 1 using star-delta transformation(7 marks) 6 (a) Explain how AC sinusoidal emf is generated?(3 marks) 6 (b) Derive equation for energy stored in capacitor.(4 marks) 6 (c) Explain in brief power measurement using two wattmeter method in 3-phase system with star connected load?(7 marks) 7 (a) List the different types of illumination scheme(3 marks) 7 (b) Define cable and explain its construction with neat sketch diagram(4 marks) 7 (c) List the different types of lamp and explain florescent lamps with wiring diagram(7 marks)

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