$A$ step-up transformer has a transformation ratio of $3:2$. What is the voltage in the secondary coil if the voltage in the primary coil is $30\, V$?

The quantity that remains unchanged in the output with respect to the input in an ideal transformer is . . . . . . .

The number of turns in the primary and secondary coils of a transformer are $50$ and $200$ respectively. If the current in the primary coil is $4 \,A$, then the current in the secondary coil is: (in $\,A$)

$A$ step-up transformer operates on $220 \,V$ and supplies a current of $2 \,A$. The ratio of primary and secondary windings is $1:20$. The current in the primary is (in $\,A$)

Voltage in the secondary coil of a transformer does not depend upon.

$A$ step-down transformer is used to reduce the main supply from $V_1$ volt to $V_2$ volt. The primary coil draws a current $I_1$ $A$ and the secondary coil draws $I_2$ $A$. $(I_1 < I_2)$. The ratio of input power to output power is