MCQ
41. The emf of a cell does not depend upon
nature of electrolyte
concentration of electrolyte
nature of material of electrodes
size and spacing of electrode
42. A de motor can be looked upon as de generator with the power flow-
Reduced
reversed
increased
modified
43. Motors used in high-speed applications have-
high torque with high speed
low torque with high speed
high torque with low speed
none of the above
44. The shunt generator gives its greatest voltage at
no load
full load
half-load
quarter load
45. The effect of a armature reaction is to-
decrease the total flux
increase the total flux
make air gape flux uniform
none of the above
46. A de motor is still used in industrial application because it
is cheap
is simple in construction
provides tine speed control
none of the above
47. Shunt are generally made of-
copper
aluminium
silver
manganin
48. The induction motor is preferred to DC motor because it-
provides high-starting torque
provide fine speed control
has simple and rugged construction
none of the above
49. The ideal de generator is one that has ---voltage regulation
low
zero
negative
positive
50. The direction of a rotation of a de motor can be determined by
Lenz's law
Fleming's left-hand rule
Fleming's right-hand rule
Ampere's law
51. What is a battery?
Current source
Voltage source
Power source
None
52. The back emf in a de motor-
opposes the applied voltage
aids the applied voltage
aids the armature current
none of the above
53. The demand for a large increase in torque of a de series motor is met by a-
large decrease in current
large decrease in speed
large increase in speed
large increase in speed
54. The greatest heat loss in a de machine is due to loss.
eddy current
hysteresis
copper
friction
55. The armature of a de machine is laminated in order to reduce-
eddy current loss.
hysteresis loss
copper loss
friction loss
56. pole de machines are most common.
2
4
6
8
57. Copper when alloyed with zinc is known as-
Brass
Bronze
Babbits
All of the above
58. Which of the following quantity maintains the same direction whether a de machine runs as a generator or as a motor?
Induced emf
Armature current
Field current
Supply current
59. The current in armature conductors of a de machine is
pure de
pulsating de
ac
pure de + pulsating de
60. The term ampere-hour (Ah) is associated with-
rectifiers
transformer
electromagnets
storage cells