In a step-up transformer, the turn ratio is $1 : 2$. A Leclanche cell $(e.m.f. = 1.5 \, V)$ is connected across the primary. The voltage developed in the secondary would be ......... $V$.

$A$ 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......$A$

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

$A$ step-down transformer has a $N_{S}$ to $N_{P}$ ratio of $1: 20$. If $8 \, V$ are developed across a $0.4 \, \Omega$ secondary load, the primary current will be: (in $ \, A$)

$A$ 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 $\%$)

"In a step-down transformer, the output current decreases." This statement is true or false?