DGVCL Exam Paper (11-12-2011) The efficiency of a transformer at full load, 0.8 p.f. lag is 90%. Its efficiency at full load, 0.8 p.f. lead will be Less than 90% 80 % More than 90% 90 % Less than 90% 80 % More than 90% 90 % ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Efficiency= output power/input powerefficiency = (v*i*cosφ)/((v*i*cosφ)+(x² Pc)+(Pi)) x=fractional part of full load
DGVCL Exam Paper (11-12-2011) It is difficult interrupt a capacitive current because Current magnitude is very small Stored energy in the capacitor is very high The restriking voltage can be high It has a leading power factor Current magnitude is very small Stored energy in the capacitor is very high The restriking voltage can be high It has a leading power factor ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) All the peripheral devices connected to a computer require power to work. Which of the following voltages is required for the motherboard to work? Positive cycle of sine wave AC DC Negative cycle of sine wave Positive cycle of sine wave AC DC Negative cycle of sine wave ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) In which of the following motors, the stator and rotor magnetic fields rotate at the same speed? Synchronous motor Induction motor Universal motor Reluctance motor Synchronous motor Induction motor Universal motor Reluctance motor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP In all machine stator and rotor magnetic field rotates (stationary with respect to each other) at synchronous speed with respect to stationary observer.
DGVCL Exam Paper (11-12-2011) Two parallel conductors are carrying the current in the same direction. Which of the following statements is correct? There is an attracting force between the conductors The force increases when the distance between the conductors is decreased There is a repelling force between the conductors The force increases when the distance between the conductors is increased There is an attracting force between the conductors The force increases when the distance between the conductors is decreased There is a repelling force between the conductors The force increases when the distance between the conductors is increased ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The picture on the monitor of a computer is made up of tiny coloured dots called Pixels Points Icons Spots Pixels Points Icons Spots ANSWER DOWNLOAD EXAMIANS APP
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