Question :

Large transformers, when used for some time, become very hot and are cooled by circulating oil. The heating of the transformer is due to


A) the heating effect of current alone
B) hysteresis loss alone
C) both the heating effect of current and hysteresis loss
D) intense sunlight at noon

Answer : C

Description :



Related Questions - 1


Rectifiers are used to convert


A) Direct current to Alternating current
B) Alternating current to Direct current
C) high voltage to low voltage
D) low voltage to high voltage

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Related Questions - 2


It is easier to roll a stone up a sloping road than to lift it vertical upwards because


A) work done in rolling is more than in lifting
B) work done in lifting the stone is equal to rolling it
C) work done in both is same but the rate of doing work is less in rolling
D) work done in rolling a stone is less than in lifting it

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Magnetism at the centre of a bar magnet is


A) minimum
B) maximum
C) zero
D) minimum or maximum

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Metals are good conductors of electricity because


A) they contain free electrons
B) the atoms are lightly packed
C) they have high melting point
D) All of the above

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Pick out the scalar quantity


A) force
B) pressure
C) velocity
D) acceleration

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