The quantity that remains unchanged in a transformer is:

The primary and secondary voltage of an ideal step-down transformer is $200 \,V$ and $25 \,V$ respectively. The secondary is connected to a device,which draws a current of $2 \,A$. The current in the primary is (in $\,mA$)

$A$ transformer is used to

Write the principle of a transformer.

The primary winding of a transformer has $500$ turns,whereas its secondary has $5000$ turns. The primary is connected to an $ac$ supply of $20\, V$,$50\, Hz$. The secondary will have an output of

$A$ step-up transformer has a transformation ratio of $5:3$. What is the voltage in the secondary coil if the voltage in the primary coil is $60 \, V$ (in $, V$)?