Download VTU ((Visvesvaraya Technological University) B.E/B-Tech 2019 July ( Bachelor of Engineering) First & Second Semester (1st Semester & 2nd Semester) 2014 June-July 10ELE15 Basic Electrical Engineering Question Paper
10ELE15/25
USN
I I
First/Second Semester B.E. Degree Examination, June / July 2014
.
Basic Electrical Engineering
Time: 3 hrs. Max. Marks:100
cc,
c. ?" Note: 1. Answer any FIVE full questions, choosing at least two from each part.
2. Answer all objective type questions only on OMR sheet page 5 of the answer booklet.
3. Answer to objective type questions on sheets other than OMR will not be valued.
v
cd
...,
bh
ii
v ,..
0
1 a. Choose the correct answers for the following : (04 Marks)
c,.. 7.
7.
q ' The resistance of a conductor is directly proportional to its and inversly
-0.
? e
proportional to its
,76 '
A) Length & Area B) Area & Length
ii
t
C) Length & Current D) Length & Voltage
'E
c
,
a
,
:r
ii) When the conductor moves perpendicular to the lines of flux, the emf induced is
c a
P 4)
A) Minimum B) Maximum C) Zero D) None of these
...)
.3)
-.
ar .?.
..'
iii) The mutual inductance between two coils of self inductance 0.8 H and 0.2 H, have a
cc
c
coefficient of coupling 0.9 is
,
cp.
8 , A) 0.36 H 13) 0.4 H C) 0.16 H D) 0.144 H ?
F cn
iv) An electric heater is rated to 2 kW, 200 Y. The resistance of the heater coil is
c., ,
9 a.
? <0 A) 10 cl B) 0.1 0 C) 20 Q % I 7b* D) 200 Q
c
-ci
----
.
. 0
b.
Show that the equivalent resistance of two resistors connected in parallel in the ratio of the
0
product of these two resistances divided by the sum of those two resistance values.
t
o
..
(04 Marks)
,i g
h.,
c. Derive an expression for dynamically induced emf. (06 Marks)
-c:J To
>, ,,
> d. Two coils having 1000 turns and 1600 turns respectively are placed close to each other such
.
?
-
cp. -
that 60% of the flux produced by one coil. If a current of 10 A, flowing in the first coil,
.c
produces a flux of 0.5 mwb. Find the inductance of the second coil. (06 Marks)
c.
a
,
z p.
o
,,,,
t.)
g 2 a. Choose the correct answers for the following : (04 Marks)
=
qa
i) An alternating current is given by i =14.14 sin o)t +
6
-
71
) has an rms value of
....
,-.
.?,
? ?...
ampereS.
bb o
c co
A) 10 A B) 14.14 C) 20 A D) 0.707
..
ii) In an a.c circuit, the ratio of kW/KVA represents
P z 1.)
? > ? A) Power factor B) Load factor C) Form factor D) Peak factor
1.
?
%
-
)
?, iii) A current drawn by a capacitor of 20 1.i.F is 1.382 A from a 220 V A.?. supply. The
supply frequency is
,
e.i
A) 25 Hz B) 60 Hz C) 50 Hz D) 40 Hz
iv) The unit of apparent power is
.-4
A) kW B) KVAR C) KVA D) Joules
,7,'
,-. b. Define: (i) Instantaneous value (ii) Amplitude (iii) Cycle (iv) Period with
respect to sinusoidally varying quantities. (04 Marks)
c. Two impedances (150 - j157) 0 and (100 + j110) 0 are connected in parallel across 200 V,
50 Hz supply. Find branch currents, total current and total power consumed in the circuit.
Draw the phasor diagram. (06 Marks)
d. Show that the power consumed in an R-C series circuit is Woos.. Draw the waveform for
voltage, current and power. (06 Marks)
PART A
1 of 3
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10ELE15/25
USN
I I
First/Second Semester B.E. Degree Examination, June / July 2014
.
Basic Electrical Engineering
Time: 3 hrs. Max. Marks:100
cc,
c. ?" Note: 1. Answer any FIVE full questions, choosing at least two from each part.
2. Answer all objective type questions only on OMR sheet page 5 of the answer booklet.
3. Answer to objective type questions on sheets other than OMR will not be valued.
v
cd
...,
bh
ii
v ,..
0
1 a. Choose the correct answers for the following : (04 Marks)
c,.. 7.
7.
q ' The resistance of a conductor is directly proportional to its and inversly
-0.
? e
proportional to its
,76 '
A) Length & Area B) Area & Length
ii
t
C) Length & Current D) Length & Voltage
'E
c
,
a
,
:r
ii) When the conductor moves perpendicular to the lines of flux, the emf induced is
c a
P 4)
A) Minimum B) Maximum C) Zero D) None of these
...)
.3)
-.
ar .?.
..'
iii) The mutual inductance between two coils of self inductance 0.8 H and 0.2 H, have a
cc
c
coefficient of coupling 0.9 is
,
cp.
8 , A) 0.36 H 13) 0.4 H C) 0.16 H D) 0.144 H ?
F cn
iv) An electric heater is rated to 2 kW, 200 Y. The resistance of the heater coil is
c., ,
9 a.
? <0 A) 10 cl B) 0.1 0 C) 20 Q % I 7b* D) 200 Q
c
-ci
----
.
. 0
b.
Show that the equivalent resistance of two resistors connected in parallel in the ratio of the
0
product of these two resistances divided by the sum of those two resistance values.
t
o
..
(04 Marks)
,i g
h.,
c. Derive an expression for dynamically induced emf. (06 Marks)
-c:J To
>, ,,
> d. Two coils having 1000 turns and 1600 turns respectively are placed close to each other such
.
?
-
cp. -
that 60% of the flux produced by one coil. If a current of 10 A, flowing in the first coil,
.c
produces a flux of 0.5 mwb. Find the inductance of the second coil. (06 Marks)
c.
a
,
z p.
o
,,,,
t.)
g 2 a. Choose the correct answers for the following : (04 Marks)
=
qa
i) An alternating current is given by i =14.14 sin o)t +
6
-
71
) has an rms value of
....
,-.
.?,
? ?...
ampereS.
bb o
c co
A) 10 A B) 14.14 C) 20 A D) 0.707
..
ii) In an a.c circuit, the ratio of kW/KVA represents
P z 1.)
? > ? A) Power factor B) Load factor C) Form factor D) Peak factor
1.
?
%
-
)
?, iii) A current drawn by a capacitor of 20 1.i.F is 1.382 A from a 220 V A.?. supply. The
supply frequency is
,
e.i
A) 25 Hz B) 60 Hz C) 50 Hz D) 40 Hz
iv) The unit of apparent power is
.-4
A) kW B) KVAR C) KVA D) Joules
,7,'
,-. b. Define: (i) Instantaneous value (ii) Amplitude (iii) Cycle (iv) Period with
respect to sinusoidally varying quantities. (04 Marks)
c. Two impedances (150 - j157) 0 and (100 + j110) 0 are connected in parallel across 200 V,
50 Hz supply. Find branch currents, total current and total power consumed in the circuit.
Draw the phasor diagram. (06 Marks)
d. Show that the power consumed in an R-C series circuit is Woos.. Draw the waveform for
voltage, current and power. (06 Marks)
PART A
1 of 3
D) None of these
(06 Marks)
the reading of each of
(05 Marks)
`a balanced 3-4) delta
(05 Marks)
10ELE15/25
3 a. Choose the correct answer:
atm
,
" (04 Marks)
i) The phase sequence or a tnree phase system is RYB. The other possible phase
sequence is
A) YRB B) BRY C) RBY D) None of these
ii) When the two wattmeters used to measure three phase power gives equal readings,
then the p.f of the circuit is given by
A) 0 B) 0.5 C) 1 D) 0.866
iii) The power consumed by a 3-4) load is given by the expression
A) 3VLILcos4) B) VaLcos4 C) V
L
ILCOS4)
iv) A 3-4) apparatus is efficient than a 1 ? 4) apparatus,
A) More B) Less C) Both (A) & (B)
What are the advantages of 3-4) systems over a single phase system?
A 3. 4), 400 V, motor takes an input of 40 kW at 0.45 p.f. lag. Find
the two single phase wattmeters connected to measure the input.
Obtain
.
the relationship between line current and phase current -in
connected system.
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c.
d.
4 a. Choose the correct answers for the following :
i) The totating disc of the energy meter is made of
A) Copper B) Silver C),Aluminum
ii) One unit of electrical energy is equivalent to
A) 3.6 kWs B) 3600 W.S C) 1 kWH
iii) An intermediate switch is used in of lamps.
A) Three way control B) Two way control
C) One way control D) Four way control
(04 Marks)
D) Platinum
D) 10 WH
iv) The value of "Fusing Factor" is always
A) Less than 1 B) Equal to 1 C) Zero D) More than 1.
b. With the help of neat diagram, explain the construction and principle of operation of a
single phase induction type energy meter. (08 Marks)
c. Write the circuit diagram and switching table for' two-way and three-way control of lamp.
Where is it used? (08 Marks)
PART ? B
5 a. Choose the correct answers for the following : (04 Marks)
i) The purpose of commutator in a d.c. generator is to
A) Increase output voltage B) Convert emf from AC to DC
C) Reduce sparking at brushes D) Increase the speed
ii) In a lap winding, the number of parallel paths is equal to
A) ?
P
B) 2P C) P D) 4P'
iii) The speed of a d.c motor is almost constant.
A) Shunt B) Series C) Compound D) None of these
iv) The torque produced by DC motor is directly proportional to
A) VI
a
B)
IaRa
C) Id
a
D) EbI
a
b. Derive the expression for the e.m.f of a DC generator. (04 Marks)
c. Sketch the various characteristics of DC shunt motor and mention its applications.
(06 Marks)
d. A DC shunt motor takes an armature current of 110 A at 480 V. The armature resistance is
0.2 a The machine has 6 poles and armature is lap connected with 864 conductors. The
flux per pole is 0.05 Wb. Calculate i) speed ii) the torque developed by the armature.
(06 Marks)
2 of 3
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10ELE15/25
USN
I I
First/Second Semester B.E. Degree Examination, June / July 2014
.
Basic Electrical Engineering
Time: 3 hrs. Max. Marks:100
cc,
c. ?" Note: 1. Answer any FIVE full questions, choosing at least two from each part.
2. Answer all objective type questions only on OMR sheet page 5 of the answer booklet.
3. Answer to objective type questions on sheets other than OMR will not be valued.
v
cd
...,
bh
ii
v ,..
0
1 a. Choose the correct answers for the following : (04 Marks)
c,.. 7.
7.
q ' The resistance of a conductor is directly proportional to its and inversly
-0.
? e
proportional to its
,76 '
A) Length & Area B) Area & Length
ii
t
C) Length & Current D) Length & Voltage
'E
c
,
a
,
:r
ii) When the conductor moves perpendicular to the lines of flux, the emf induced is
c a
P 4)
A) Minimum B) Maximum C) Zero D) None of these
...)
.3)
-.
ar .?.
..'
iii) The mutual inductance between two coils of self inductance 0.8 H and 0.2 H, have a
cc
c
coefficient of coupling 0.9 is
,
cp.
8 , A) 0.36 H 13) 0.4 H C) 0.16 H D) 0.144 H ?
F cn
iv) An electric heater is rated to 2 kW, 200 Y. The resistance of the heater coil is
c., ,
9 a.
? <0 A) 10 cl B) 0.1 0 C) 20 Q % I 7b* D) 200 Q
c
-ci
----
.
. 0
b.
Show that the equivalent resistance of two resistors connected in parallel in the ratio of the
0
product of these two resistances divided by the sum of those two resistance values.
t
o
..
(04 Marks)
,i g
h.,
c. Derive an expression for dynamically induced emf. (06 Marks)
-c:J To
>, ,,
> d. Two coils having 1000 turns and 1600 turns respectively are placed close to each other such
.
?
-
cp. -
that 60% of the flux produced by one coil. If a current of 10 A, flowing in the first coil,
.c
produces a flux of 0.5 mwb. Find the inductance of the second coil. (06 Marks)
c.
a
,
z p.
o
,,,,
t.)
g 2 a. Choose the correct answers for the following : (04 Marks)
=
qa
i) An alternating current is given by i =14.14 sin o)t +
6
-
71
) has an rms value of
....
,-.
.?,
? ?...
ampereS.
bb o
c co
A) 10 A B) 14.14 C) 20 A D) 0.707
..
ii) In an a.c circuit, the ratio of kW/KVA represents
P z 1.)
? > ? A) Power factor B) Load factor C) Form factor D) Peak factor
1.
?
%
-
)
?, iii) A current drawn by a capacitor of 20 1.i.F is 1.382 A from a 220 V A.?. supply. The
supply frequency is
,
e.i
A) 25 Hz B) 60 Hz C) 50 Hz D) 40 Hz
iv) The unit of apparent power is
.-4
A) kW B) KVAR C) KVA D) Joules
,7,'
,-. b. Define: (i) Instantaneous value (ii) Amplitude (iii) Cycle (iv) Period with
respect to sinusoidally varying quantities. (04 Marks)
c. Two impedances (150 - j157) 0 and (100 + j110) 0 are connected in parallel across 200 V,
50 Hz supply. Find branch currents, total current and total power consumed in the circuit.
Draw the phasor diagram. (06 Marks)
d. Show that the power consumed in an R-C series circuit is Woos.. Draw the waveform for
voltage, current and power. (06 Marks)
PART A
1 of 3
D) None of these
(06 Marks)
the reading of each of
(05 Marks)
`a balanced 3-4) delta
(05 Marks)
10ELE15/25
3 a. Choose the correct answer:
atm
,
" (04 Marks)
i) The phase sequence or a tnree phase system is RYB. The other possible phase
sequence is
A) YRB B) BRY C) RBY D) None of these
ii) When the two wattmeters used to measure three phase power gives equal readings,
then the p.f of the circuit is given by
A) 0 B) 0.5 C) 1 D) 0.866
iii) The power consumed by a 3-4) load is given by the expression
A) 3VLILcos4) B) VaLcos4 C) V
L
ILCOS4)
iv) A 3-4) apparatus is efficient than a 1 ? 4) apparatus,
A) More B) Less C) Both (A) & (B)
What are the advantages of 3-4) systems over a single phase system?
A 3. 4), 400 V, motor takes an input of 40 kW at 0.45 p.f. lag. Find
the two single phase wattmeters connected to measure the input.
Obtain
.
the relationship between line current and phase current -in
connected system.
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c.
d.
4 a. Choose the correct answers for the following :
i) The totating disc of the energy meter is made of
A) Copper B) Silver C),Aluminum
ii) One unit of electrical energy is equivalent to
A) 3.6 kWs B) 3600 W.S C) 1 kWH
iii) An intermediate switch is used in of lamps.
A) Three way control B) Two way control
C) One way control D) Four way control
(04 Marks)
D) Platinum
D) 10 WH
iv) The value of "Fusing Factor" is always
A) Less than 1 B) Equal to 1 C) Zero D) More than 1.
b. With the help of neat diagram, explain the construction and principle of operation of a
single phase induction type energy meter. (08 Marks)
c. Write the circuit diagram and switching table for' two-way and three-way control of lamp.
Where is it used? (08 Marks)
PART ? B
5 a. Choose the correct answers for the following : (04 Marks)
i) The purpose of commutator in a d.c. generator is to
A) Increase output voltage B) Convert emf from AC to DC
C) Reduce sparking at brushes D) Increase the speed
ii) In a lap winding, the number of parallel paths is equal to
A) ?
P
B) 2P C) P D) 4P'
iii) The speed of a d.c motor is almost constant.
A) Shunt B) Series C) Compound D) None of these
iv) The torque produced by DC motor is directly proportional to
A) VI
a
B)
IaRa
C) Id
a
D) EbI
a
b. Derive the expression for the e.m.f of a DC generator. (04 Marks)
c. Sketch the various characteristics of DC shunt motor and mention its applications.
(06 Marks)
d. A DC shunt motor takes an armature current of 110 A at 480 V. The armature resistance is
0.2 a The machine has 6 poles and armature is lap connected with 864 conductors. The
flux per pole is 0.05 Wb. Calculate i) speed ii) the torque developed by the armature.
(06 Marks)
2 of 3
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LIBRARY
12
D) ?
E
2
N
2
N
1
ii) The efficiency of a transformer is maximum when
A) Iron loss is more than copper loss B) Iron loss is equal to copper loss
C) Iron loss is less than copper loss D) None of these
iii) Core type of transformers are used to handle and voltages.
A) Low and High B) Low and Medium C) High and Medium D) None of these
iv) Copper loss in a transformer is a loss.
A) Constant loss B) Variable loss C) Friction loss D) None of these
b. Explain the construction and working of a transformer. (06 Marks)
c. Find .the number of turns on the primary and secondary side of a 440/230 V, 50 Hz single
phase transformer, if the net area of cross section of the core is 30 cm
2
and the maximum
flux density is 1 Whin1
2
. (04 Marks)
d. A single phase transformer working at 0.8 pf has an efficiency 94% at both three fourth full
load and full load-of 600 kW. Determine the efficiency at half full ?load, unity power factor.
(06 Marks)
7 a. Choose the correct answers for the following : (04 Marks)
i) A non salient pole rotor is used in alternator.
A) Low speed B) High speed C) Medium speed D) A and B
ii) The speed at which a 4?pole alternator has to be driven to generate a voltage at 50 Hz
is Armik
-
N..
A) 1000 rpm B) 1500 rpm C) 2000 rpm . D) 1440 rpm
iii) The E. M. F. induced in an alternatpr is given by the equation '
A) 4.44 ftli z k
p
k
d
B) 2.22 k
p
z C) 2.22 f z k
p
kd D) 4.44 f z
iv) The field winding of an alternator is excited.
A) DC B) AC C) Both DC and AC D) None of these
b. How are alternators classified? With a neat diagram, show the difference between them.
(08 Marks)
c. A 2 ? pole, 3 ? phase alternator running at 3000 rpm has armature slots with 2 conductors in
each slot. Calculate the flux per pole required to generate a line voltage of 2300 V.
Distribution factor is 0.952 and pitch factor is 0.956. (06 Marks)
d. Define regulation of an alternator. (02 Marks)
8 a. Choose the correct answers for the following :
(04 Marks)
i) The
frequency of the rotor current is
A) X. B) sf C) sf
2
D) None of these
ii) In a 3 ? phase induction motor, the slip speed is given by
A) N
s
B) N C) Ns ? N D) N ? Ns
iii) The synchronous speed of three phase induction motor is given by
Ns
Pf
A) n s =
120f
B) Ns = 120 fP C)
120P
? N
s
D) Ns
0 P 12
iv) A 3 ? (I) induction motor having 4 ? poles, 50 Hz runs at 1440 rpm, the slip is
A) 3% B) 5% C) 4% D) 1%
b. With a neat diagram, explain the working principle of 3 - induction motor. (06 Marks)
C. A 10 pole induction motor is supplied by a 6 ? pole alternator which is driven at 1200 rpm.
If the motor runs with a slip of 3%, what is its speed? (06 Marks)
d. Why does an induction motor need a starter? (04 Marks)
10ELE15/25
e?46
0. on099
6 a. Choose the correct answers _
(04 Marks)
i) The transformation ratio in a transformer is equal to
A) ?I B) Ni C)
N2
3 of 3
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This post was last modified on 01 January 2020