List of top Physics Questions on Transformers

The output of a step down transformer is measured to be $48\, V$ when connected to a ${12 \, W}$ bulb. The value of peak current is
A transformer connected to 220 V mains is used to light a lamp of rating 100 W and 110 V. If the primary current is 0.5 A, the efficiency of the transformer is (approximately)
A step down transformer increases the input current 4 A to 24 A at the secondary. If the number of turns in the primary coil is 330, the number of turns in the secondary coil is
A step down transformer increases the input current 4 A to 24 A at the secondary. If the number of turns in the primary coil is 330, the number of turns in the secondary coil is
A step down transformer increases the input current 4 A to 24 A at the secondary. If the number of turns in the primary coil is 330, the number of turns in the secondary coil is
The alternating e.m.f. induced in the secondary coil of a transformer is mainly due to
An observer looks at a tree of height 15 m with a telescope of magnifying power 10. To him the tree appears
The ratio of secondary and primary turns of step-up transformer is 4 : 1. If a current of 4 A is applied to the primary, the induced current in secondary will be
A primary coil and secondary coil are placed close to each other. A current, which changes at the rate of 25 A in a millisecond, is present in the primary coil. If the mutual inductance is $92 \times 10^{-6} H$, then the value of induced emf in the secondary coil is
Which quantity is increased in step-down transformer?
In a step-up transformer the turn ratio is 1:2. A Leclanché cell (emf 1.5 V) is connected across the primary. The voltage across the secondary is:
The number of turns in primary coil of a transformer is 20 and the number of turns in the secondary is 10. If the voltage across the primary is 220 V, what is the voltage across the secondary?
A transformer cannot work on $DC$ supply. $DC$ changes neither in magnitude nor in direction.
The core of any transformer is laminated so as to
A transformer of 100% efficiency has 200rums in the primary and 40000 turns in secondary. It is connected to a 220 V main supply and secondary feeds to a 100 $ K\Omega $ resistance. The potential difference per turn is
The ore that is concentrated by froth floatation process is
A step-up transformer operates on a 230 V line and supplies a load of 2 A. The ratio of primary to secondary windings is 1:25. The current in the primary is:
If the coefficient of mutual induction of the primary and secondary coils of an induction coil is $5\, H$ and a current of $10 A$ is cut-off in $5 \times 10^{-4} s$, the emf inducted (in volt) in the secondary coil is :
Core of a transformer is made up of:
Transformer is based upon the principle of:
The core of a transformer is laminated to reduce
The current drawn by the primary of a transformer, which steps down $200\,V$ to $20\,V$ to operate a device of resistance $20\,\Omega $. is (Assume the efficiency of the transformer to be $80\, \%$)
Transformer is used to
The coupling coefficient of the perfectly coupled coils is :
Rectifier converts: