Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Winter 1st And 2nd Sem New And Spfu 2110005 Elements Of Electrical Engineering Previous Question Paper
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? I & II (NEW) EXAMINATION ? WINTER 2019
Subject Code: 2110005 Date: 11/01/2020
Subject Name: Elements of Electrical Engineering
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Question No. 1 is compulsory. Attempt any four out of remaining Six questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 Objective Question (MCQ)
Mark
(a) 07
1. A circuit contains two unequal resistances in parallel
[a] current is same in both
[b] large current flows in larger resistance
[c] potential difference across each is same
[d] smaller resistance has smaller conductance
2. Which medium has least dielectric strength?
[a] Air [b] Quartz [c] Glass [d] Paraffin wax
3. Which of the following is a vector quantity?
[a] Magnetic potential [b] Magnetic field intensity
[c] Flux density [d] Relative permeability
4. If the current and voltage are out of phase by 90?, the power is
[a] Minimum [b] Maximum [c] Zero [d] 1.1 *V*I
5. In ac circuits, the ac meters measure
[a] RMS values [b] Peak values
[c] Mean value [d] Mean square value
6. Which of the following statement is not correct?
[a] A primary cell is an electrochemical cell
[b] After charging, a primary cell can be again put to use
[c] Dry cell is a primary cell
[d] Leclanche cell is used in experiments, where constant supply of
current is not needed.
7. Candela is the unit for
[a] Light flux [b] Brightness
[c] Luminous efficiency [d] Luminous intensity
(b) 07
1. A resistor is to be connected across a 45 V battery to provide 1 mA
of current. The required resistance with a suitable wattage rating is
[a] 45 ?, 10W [b] 4.5 ?, 2 W
[c] 450 k?, 20W [d] 45 k?, ? W
2. The capacitance reactance of an ac circuit containing 35?F
capacitance at a frequency of 60 Hz will be
[a] 50 ? [b] 60 ? [c] 75 ? [d] 100 ?
3. A property of a material which opposes the creation of magnetic flux
in it is known as
[a] magneto motive force [b] reluctance
[c] permeance [d] reluctivity
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Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? I & II (NEW) EXAMINATION ? WINTER 2019
Subject Code: 2110005 Date: 11/01/2020
Subject Name: Elements of Electrical Engineering
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Question No. 1 is compulsory. Attempt any four out of remaining Six questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 Objective Question (MCQ)
Mark
(a) 07
1. A circuit contains two unequal resistances in parallel
[a] current is same in both
[b] large current flows in larger resistance
[c] potential difference across each is same
[d] smaller resistance has smaller conductance
2. Which medium has least dielectric strength?
[a] Air [b] Quartz [c] Glass [d] Paraffin wax
3. Which of the following is a vector quantity?
[a] Magnetic potential [b] Magnetic field intensity
[c] Flux density [d] Relative permeability
4. If the current and voltage are out of phase by 90?, the power is
[a] Minimum [b] Maximum [c] Zero [d] 1.1 *V*I
5. In ac circuits, the ac meters measure
[a] RMS values [b] Peak values
[c] Mean value [d] Mean square value
6. Which of the following statement is not correct?
[a] A primary cell is an electrochemical cell
[b] After charging, a primary cell can be again put to use
[c] Dry cell is a primary cell
[d] Leclanche cell is used in experiments, where constant supply of
current is not needed.
7. Candela is the unit for
[a] Light flux [b] Brightness
[c] Luminous efficiency [d] Luminous intensity
(b) 07
1. A resistor is to be connected across a 45 V battery to provide 1 mA
of current. The required resistance with a suitable wattage rating is
[a] 45 ?, 10W [b] 4.5 ?, 2 W
[c] 450 k?, 20W [d] 45 k?, ? W
2. The capacitance reactance of an ac circuit containing 35?F
capacitance at a frequency of 60 Hz will be
[a] 50 ? [b] 60 ? [c] 75 ? [d] 100 ?
3. A property of a material which opposes the creation of magnetic flux
in it is known as
[a] magneto motive force [b] reluctance
[c] permeance [d] reluctivity
4. If one cycle of ac waveform occurs every milli-second, the frequency
will be
[a] 1/1000 Hz [b] 50 Hz [c] 100 Hz [d] 1000 Hz
5. In an ac source R=36 ?, frequency = 50 Hz and L = 0.12 H, then
phase difference between current and voltage is nearly
[a] 90? [b] 60? [c] 45? [d] 75?
6. In a lead acid battery, during charging
[a] anode becomes whitish in colour [b] voltage drops
[c] specific gravity of acid increases [d] the cell gives out energy
7. In a fluorescent tube circuit, choke acts as
[a] starter [b] power factor improving device
[c] source of heat [d] current limiting device
Q.2 (a) Two wires A & B made up of same material, wire B has twice the
length of wire A and having half the diameter to that of A. Calculate
the ratio RB/RA.
03
(b) Why domestic appliances are connected in parallel? Give
comparison with series circuit?
04
(c) Three resistances R AB, RBC and RCA are connected in delta. Obtain
expressions for their equivalent star resistances.
07
Q.3 (a) State and explain Coulomb?s laws. 03
(b) Discuss B-H curve of a ferro-magnetic material and explain the
following. (i) Magnetic saturation (ii) Hysterisis (iii) Residual
Magnetism (iv) coercive force.
04
(c) A capacitor of 0.1 ?F is charged from a 100 V battery through a series
resistance of 1 K?. Find
(i) The time for the capacitor to receive 63.2% of its final charge.
(ii) The charge received in this time
(iii) The final rate of charging
(iv) The rate of charging when the charge is 63.2% of the final
charge.
07
Q.4 (a) Give comparison between magnetic and electric circuits. 03
(b) Derive an expression for the equivalent capacitance of a group of
capacitors when they are connected (i) in parallel (ii) in series.
04
(c) A ring composed of three sections. The cross-sectional area is 0.001
m
2
for each section. The mean arc length are Ia = 0.3 m, Ib = 0.2 m,
Ic = 0.1 m. An air-gap length of 0.1 mm is cut in the ring. ?r for
sections a, b, c are 5000, 1000 and 10,000 respectively. Flux in the
air gap is 7.5 X 10
-4
Wb. Find (i) mmf (ii) exciting current if the coil
has 100 turns. (iii) Reluctance of the sections.
07
Q.5 (a) Define: (i) r.m.s. value (ii) Form factor (iii) Amplitude factor 03
(b) Distinguish between (i) apparent power (ii) active power and (iii)
reactive power in ac circuits.
04
(c) What is resonance in AC circuit? Elaborate resonance in case of
series R-L-C circuit with the help of phasor diagram and sketch the
resonance curve.
07
Q.6 (a) List out the merits of two watt meter method. 03
FirstRanker.com - FirstRanker's Choice
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ? I & II (NEW) EXAMINATION ? WINTER 2019
Subject Code: 2110005 Date: 11/01/2020
Subject Name: Elements of Electrical Engineering
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Question No. 1 is compulsory. Attempt any four out of remaining Six questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 Objective Question (MCQ)
Mark
(a) 07
1. A circuit contains two unequal resistances in parallel
[a] current is same in both
[b] large current flows in larger resistance
[c] potential difference across each is same
[d] smaller resistance has smaller conductance
2. Which medium has least dielectric strength?
[a] Air [b] Quartz [c] Glass [d] Paraffin wax
3. Which of the following is a vector quantity?
[a] Magnetic potential [b] Magnetic field intensity
[c] Flux density [d] Relative permeability
4. If the current and voltage are out of phase by 90?, the power is
[a] Minimum [b] Maximum [c] Zero [d] 1.1 *V*I
5. In ac circuits, the ac meters measure
[a] RMS values [b] Peak values
[c] Mean value [d] Mean square value
6. Which of the following statement is not correct?
[a] A primary cell is an electrochemical cell
[b] After charging, a primary cell can be again put to use
[c] Dry cell is a primary cell
[d] Leclanche cell is used in experiments, where constant supply of
current is not needed.
7. Candela is the unit for
[a] Light flux [b] Brightness
[c] Luminous efficiency [d] Luminous intensity
(b) 07
1. A resistor is to be connected across a 45 V battery to provide 1 mA
of current. The required resistance with a suitable wattage rating is
[a] 45 ?, 10W [b] 4.5 ?, 2 W
[c] 450 k?, 20W [d] 45 k?, ? W
2. The capacitance reactance of an ac circuit containing 35?F
capacitance at a frequency of 60 Hz will be
[a] 50 ? [b] 60 ? [c] 75 ? [d] 100 ?
3. A property of a material which opposes the creation of magnetic flux
in it is known as
[a] magneto motive force [b] reluctance
[c] permeance [d] reluctivity
4. If one cycle of ac waveform occurs every milli-second, the frequency
will be
[a] 1/1000 Hz [b] 50 Hz [c] 100 Hz [d] 1000 Hz
5. In an ac source R=36 ?, frequency = 50 Hz and L = 0.12 H, then
phase difference between current and voltage is nearly
[a] 90? [b] 60? [c] 45? [d] 75?
6. In a lead acid battery, during charging
[a] anode becomes whitish in colour [b] voltage drops
[c] specific gravity of acid increases [d] the cell gives out energy
7. In a fluorescent tube circuit, choke acts as
[a] starter [b] power factor improving device
[c] source of heat [d] current limiting device
Q.2 (a) Two wires A & B made up of same material, wire B has twice the
length of wire A and having half the diameter to that of A. Calculate
the ratio RB/RA.
03
(b) Why domestic appliances are connected in parallel? Give
comparison with series circuit?
04
(c) Three resistances R AB, RBC and RCA are connected in delta. Obtain
expressions for their equivalent star resistances.
07
Q.3 (a) State and explain Coulomb?s laws. 03
(b) Discuss B-H curve of a ferro-magnetic material and explain the
following. (i) Magnetic saturation (ii) Hysterisis (iii) Residual
Magnetism (iv) coercive force.
04
(c) A capacitor of 0.1 ?F is charged from a 100 V battery through a series
resistance of 1 K?. Find
(i) The time for the capacitor to receive 63.2% of its final charge.
(ii) The charge received in this time
(iii) The final rate of charging
(iv) The rate of charging when the charge is 63.2% of the final
charge.
07
Q.4 (a) Give comparison between magnetic and electric circuits. 03
(b) Derive an expression for the equivalent capacitance of a group of
capacitors when they are connected (i) in parallel (ii) in series.
04
(c) A ring composed of three sections. The cross-sectional area is 0.001
m
2
for each section. The mean arc length are Ia = 0.3 m, Ib = 0.2 m,
Ic = 0.1 m. An air-gap length of 0.1 mm is cut in the ring. ?r for
sections a, b, c are 5000, 1000 and 10,000 respectively. Flux in the
air gap is 7.5 X 10
-4
Wb. Find (i) mmf (ii) exciting current if the coil
has 100 turns. (iii) Reluctance of the sections.
07
Q.5 (a) Define: (i) r.m.s. value (ii) Form factor (iii) Amplitude factor 03
(b) Distinguish between (i) apparent power (ii) active power and (iii)
reactive power in ac circuits.
04
(c) What is resonance in AC circuit? Elaborate resonance in case of
series R-L-C circuit with the help of phasor diagram and sketch the
resonance curve.
07
Q.6 (a) List out the merits of two watt meter method. 03
(b) Phase voltage and current of a star-connected inductive load is 150
V and 25 A. Power factor of load is 0.707 (lag). Assuming that the
system is 3-wire and power is measured using two wattmeters, find
the readings of wattmeters.
04
(c) Obtain the relationship between line and phase values of current in a
three phase, balanced, delta connected system.
07
Q.7 (a) List out the different types of illumination schemes. 03
(b) Discuss the Lead acid battery with charging & discharging equations. 04
(c) Define term ?earthing?. State all the methods of earthing and explain any
one of them.
07
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This post was last modified on 20 February 2020