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 $\,A$)

An $80 \text{ W}$ lamp is connected to the secondary of a step-down transformer, where the primary is connected to an $AC$ mains of $220 \text{ V}$. Assuming the transformer to be ideal, the current in the primary winding is nearly: (in $\text{ A}$)

$A$ generator at a utility company produces $100 \, A$ of current at $4000 \, V$. The voltage is stepped up to $240,000 \, V$ by a transformer before it is sent on a high voltage transmission line. The current in the transmission line is ....... $A$.

In a step-up transformer,which one of the following statements is correct?

$A$ 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 $A$)

$A$ transformer having efficiency $90 \%$ is working on $200 \ V$ and $3 \ kW$ power supply. If the current in the secondary coil is $6 \ A$, the voltage across the secondary coil and the current in the primary coil are respectively: