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 coil of a transformer is $1000$ and in the secondary coil is $3000$. If $80 \ V$ a.c. is applied to the primary,the potential difference per turn of the secondary coil is: (in $V$)

$A$ power transmission line feeds input power at $2300\,V$ to a step-down transformer with its primary windings having $4000$ turns,giving the output power at $230\,V.$ If the current in the primary of the transformer is $5\,A,$ and its efficiency is $90\%,$ the output current would be......$A$

The number of turns in the primary and secondary coils of a transformer are $50$ and $200$ respectively. If the current in the primary coil is $4 \,A$, then the current in the secondary coil is: (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.....$A$.

In a step-up transformer,the turn ratio is $8:1$. $A$ $60\,Hz, 120\,V$ input is connected to its primary coil. The load resistance in the secondary coil is $10^4\,\Omega$. Find the current in the secondary coil.