2018 FEBRUARY ELECTRICIAN
THEORY SEMESTER-II PART-2
26. For a constant torque load,
if the
armature resistance of
shunt
motor is doubled (keeping
the shunt
field constant) then the
armature current will become-
a) Double
b) Halved
c) Remain
same
d) None of
these
Answer:- c) Remain same
27. Light
used in the front yard
of the
house should not attract
insect in view of safety. Which
type of lamp you will avoid?
type of lamp you will avoid?
a)
Mercury vapor lamp
b) Sodium vapor lamp
c)
Halogen lamp
d) GLS
lamp
Answer:- a) Mercury vapor lamp
28.What
is the temperature at which
a gas
filled tungsten filament lamp
operates?
a) 1035° C
a) 1035° C
b)1200°
c) 1500°C
c) 1500°C
d)2300°C
Answer:- d)2300°C
29. A 4
pole, 220 V, 10 H.P, d.c.
shunt
motor is rotating at a speed
of 320
rpm. The developed useful
torque will be-
a)
210.647 N-m
b)
215.547 N-m
c)
219.484 N-m
d) None
of these
Answer:- c) 219.484 N-m
30. The
maximum value of sine wave
of AC
voltage is 10V. What is its
RMS
value?
a) 1.414 V
a) 1.414 V
b) 6.060
V
c) 7.070
V
d) 14.140
V
Answer:- c) 7.070 V
31. Which
of the following oscillators
is suitable for frequencies in the range
of mega
hertz?
a) RC phase shift
a) RC phase shift
b) Wien
bridge
c)
Hartley
d) Both
(a) and (c)
Answer:- c) Hartley
32. In a
BJT circuit a pnp transistor is
replaced
by npn transistor. To analyze
the new circuit-
a) All
calculations done earlier have
to be repeated
b)
Replace all calculated voltages
by reverse values
c)
Replace all calculated currents by
reverse values
d)
Replace all calculated voltages and
currents by river values
Answer:- d) Replace all calculated
voltages and
currents by river values
33. When
the value of capacitance is
increased
in series resistance circuit,
the
frequency will-
a) Decrease
b) Increase
a) Decrease
b) Increase
c) No
change
d) Becomes zero
d) Becomes zero
Answer:- a) Decrease
34. The output indicated on the name
plate of
any motor is always the-
a) Gross
power
b) Power
drawn in volt amperes
c) Power
drawn in watts
d) Output
power at the shaft
Answer:- d) Output power at the shaft
35. To
protect the diodes in a rectifier
and
capacitor input filter circuit it is
necessary
to use-
a) Surge resistor
a) Surge resistor
b) Surge
inductor
c) Surge
capacitor
d) Both
(a) and (b)
Answer:- a) Surge
resistor
36. The
D.C shunt motor speed is
to be
varied from zero to above
normal
with reversing facility having
inherent
stability of speed at all loads.
What
speed control method is to be
used?
used?
a) Supply
voltage speed control
method
b)
Ward-Leonard system of
speed control
c) Shunt field control method
c) Shunt field control method
d)
Armature speed control method
Answer:- b) Ward-Leonard system of
speed control
37. An RC
oscillator uses-
a) One RC
combination
b) Two RC
combinations
c) At
last three RC combinations
d) Either
(a) or (b)
Answer:- c) At last
three RC combinations
38, You notice that a D.C
motor starts
with jerk
when starting the motor.
What may
be fault for this effect?
a) line
voltage too high
b) Short
circuit of the field winding
c) Pitted
starter contact terminals
d) Wrong grade
of carbon brushes
Answer:- c) Pitted starter contact
terminals
39. The
gain of an FET amplifier
can be
changed by changing-
a) rm
b)gm
c) Rd
d) None
of these
Answer:- b)gm
40. The
direction of rotation of a
D.C motor
is determined by_.
a)
Fleming's right hand rule
b)
Fleming's left hand rule
c)
Ampere's right hand grip rule
d)
Maxwell's cork screw rule
Answer:- b) Fleming's left hand rule
41. A 220V, DC machine has an
armature
resistance of 0.5 ohm.
If the
armature current is amps,
the
induced emf when the machine
work as-
(i)
Generator
(ii)
Motor will be respectively
a) 220V,
210V
b) 210V,
230V
c) 200V,
230V
d) 190V,
240V
Answer:- b) 210V, 230V
42. The
D.C motor works on
the principle that the-
a)
Current carrying conductor
placed in a uniform magnetic
field
experiences a force on it
b)
Conductor moves when kept
in a uniform magnetic field
c)
Magnetic field set up by varying
current
which produces force in the
conductor
d)
Combined magnetic field set up
by two
current carrying conductors
produces
a force between them
Answer:- a) Current carrying
conductor
placed in a uniform magnetic
field
experiences a force on it
43. A DC
shunt motor is running on
no-load.
If the field winding gets
opened,
what will be the condition
of the
motor?
a) The
motor will stop
b) The
motor will burn out
c) The
motor will run at high speed
d) The
motor will make noise
Answer:- a) The
motor will stop
44. The starting current of
a 220V.
10 HP
shunt motor having an
armature resistance
of 0.2 ohms,
without
starter is_.
a) 11
amps
b) 110
amps
c) 1100
amps
d) 11000
amps
Answer:- c) 1100 amps
45. The
starting resistance of 3 point
starter
in D.C motor is connected with_
a)
Parallel across the armature
b) Series
with the armature
c) Parallel
across the field winding
d) Series
with the field winding
Answer:- b) Series with the armature
46. The
standard rated value of secondary
current
of current transformer as per IS 2705
(Part 1) - 1981 shall be either_.
(Part 1) - 1981 shall be either_.
a) 5
Ampere or 10 Ampere
b) 2.5
Ampere or 5 Ampere
c) 1.5
Ampere or 6 Ampere
d) 1
Ampere or 5 Ampere
Answer:- d) 1 Ampere or 5 Ampere
47. The
rated secondary voltage of a
single phase potential transformer is
a) 240V
a) 240V
b) 230V
c) 115V
d)110V
Answer:- d)110V
48.
Efficiency of transformer is
determined
by knowing its input
and
output power. What is the unit
used for
input and output when
calculating
the all day efficiency?
a) KVAR
a) KVAR
b) KW
c) KVA
d) KWh
Answer:- d) KWh
49. The
function of conservator in a
transformer
is_
a) To
prevent flow of moisture into
the tank
b) To
prevent flow of air into the tank
c) To
regulate the expansion and
contraction of oil
d) To
improve power factor
Answer:- c) To regulate the expansion
and
contraction of oil
50. What
will happen to 415V/240V,
1KVA
transformer when it is connected
to a D.C supply?
a) The
output will be 240V
b) The output will be 415V
c) The
transformer may burn .
d) Remain
as it is
Answer:- c) The
transformer may burn
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