$A$ transformer with $80 \%$ efficiency works at $4 \text{ kW}$ and $100 \text{ V}$. If the secondary voltage is $240 \text{ V}$, then the primary current is . . . . . . . (in $A$)

The transformation ratio in a step-up transformer is

In a transformer,the number of turns in primary and secondary are $500$ and $2000$ respectively. If the current in the primary is $48 \ A$,the current in the secondary is......$A$.

$A$ step-down transformer is connected to a $2400 \, V$ line, and $80 \, A$ of current is found to flow in the output load. The ratio of the turns in the primary and secondary coil is $20 : 1$. If the transformer efficiency is $100\%$, then the current flowing in the primary coil will be: (in $A$)

$A$ step-down transformer transforms $220 \text{ V}$ to $11 \text{ V}$. If the currents in the primary and secondary coils are $5 \text{ A}$ and $90 \text{ A}$ respectively,the efficiency of the transformer is: (in $\%$)

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 $\,A$)