113. In case of conlactors, the duty in which the main contacts remain closed for a period bearing a definate relation to the no-load periods, is known as
A. Standard duty
B. Intermittent duty
C. Temporary duty
D. Un-interrupted duty
114. In case of contactors the ratio of the in-service period to the entire period, expressed as a percentage is known as
A. duty
B. load factor
C. class of contact
D. none of these
115. Heat control switches find applications in
A. three-phase induction motors
B. single phase motors
C. transformers
D. cooling yanges.
116. A magnetic amplifier can be used for the control of
A. current
B. voltage
C. speed
D. all of these
117. In a contactor, overheating of contacts may result from
A. high inductive loads
B. copper oxide on contacts
C. carrying load continuously for a longer time
D. all of these
118. According to Indian Electricity rules, extra high voltage implies voltage exceeding
A. 440V
B. 66kV
C. 33kV
D. 110kV
119. Non metallic conduits for wiring are generally made of
A. rubber
B. cork
C. wood
D. PVC
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