The ratio of secondary to primary turns is $9:4$. If power input is $P$, what will be the ratio of power output (neglect all losses) to power input?

$A$ step-up transformer operates on a $230\, V$ line and supplies a load of $2\, A$. The ratio of the primary and secondary windings is $1 : 25$. The current in the primary is.... (in $, A$)

In a step-up transformer,$220 \, V$ is converted into $2200 \, V$. The number of turns in the primary coil is $600$. What is the number of turns in the secondary coil?

In a step-up transformer,the turn ratio is $8:1$. $A$ $60\,Hz, 120\,V$ input is connected to its primary coil. The load resistance in the secondary coil is $10^4\,\Omega$. Find the current in the secondary coil.

An ideal transformer has $100$ turns in the primary and $250$ turns in the secondary. The peak value of the $ac$ input voltage is $28 \, V$. The r.m.s. secondary voltage is nearest to.....$V$

The efficiency of a transformer is very high because