How much current is drawn by the primary coil of a transformer,which steps down $220 V$ to $55 V$ to operate a device with an impedance of $275 \Omega$ (in $A$)?

In a transformer,the number of turns in the primary coil is $140$ and in the secondary coil is $280$. If the current in the primary coil is $4\,A$,then the current in the secondary coil is.....$A$.

The quantity that remains unchanged in the output with respect to the input in an ideal transformer is . . . . . . .

The number of turns in the primary and secondary coils of a transformer are $100$ and $20$ respectively. If an alternating potential of $200 \, V$ is applied to the primary,the induced potential in the secondary will be......$V$.

The core of a transformer is made up of:

For an ideal transformer,if $N_S > N_P$,then . . . . . . .