The instrument which works on the principle of mutual inductance is

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.

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

$A$ step-up transformer operates on a $220 \,V$ line and supplies $2.2 \,A$. The ratio of primary to secondary winding turns is $11:50$. The output voltage in the secondary is .......... $V$.

The number of turns in the primary coil of a transformer is $1000$ and in the secondary coil is $3000$. If $80 \ V$ a.c. is applied to the primary,the potential difference per turn of the secondary coil is: (in $V$)

In a step-up transformer, the turn ratio is $1:10$. A resistance of $200 \, \Omega$ connected across the secondary is drawing a current of $0.5 \, A$. What is the primary voltage and current?