The output voltage of an ideal transformer,connected to a $240 \, V$ $a.c.$ mains,is $24 \, V$. When this transformer is used to light a bulb with rating $(24 \, V, 24 \, W)$,calculate the current in the primary coil of the circuit.

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......$A$.

The primary coil of a transformer is connected to a $220 \,V$ $AC$ source. The number of turns in the primary and secondary coils are $100$ and $10$ respectively. The secondary coil is connected to two resistors in series as shown in the figure. The output voltage $\left(V_0\right)$ is: (in $\,V$)

Large transformers,when used for some time,become hot and are cooled by circulating oil. The heating of a transformer is due to:

$A$ transformer is used to light a $100 \,W-110 \,V$ lamp from a $220 \,V$ mains. If the main current is $0.5 \,A$, the efficiency of the transformer is: (in $\%$)

$A$ transformer has a turn ratio of $100/1$. If the secondary coil has a $4 \, A$ current,then the current in the primary coil is......$A$