In a lossless transformer,an alternating current of $2 \ A$ is flowing in the primary coil. The number of turns in the primary and secondary coils are $100$ and $20$ respectively. The value of the current in the secondary coil is.......$A$

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 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 $\%$)

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

$A$ power transmission line feeds input power at $2300 \ V$ to a step-down transformer with its primary winding having $4000$ turns. What should be the number of turns in the secondary in order to get output power at $230 \ V$?

Which device is used to transmit voltage over large distances and why?