$A$ step-down transformer has a turns ratio of $20:1$. If $8 \, V$ is applied across a $0.4 \, \Omega$ secondary coil, then the primary current will be: (in $ \, A$)

$A$ loss-free transformer has $500$ turns on its primary winding and $2500$ turns in its secondary winding. The meters of the secondary indicate $200 \, V$ at $8 \, A$ under these conditions. The voltage and current in the primary are:

$A$ transformer is used to light a $100\,W$ and $110\,V$ lamp from a $220\,V$ main. If the main current is $0.5\,A$, the efficiency of the transformer is approximately .....$\%$

$A$ step-down transformer converts transmission line voltage from $11000 \, V$ to $220 \, V$. The primary of the transformer has $6000 \, \text{turns}$ and the efficiency of the transformer is $60 \%$. If the output power is $9 \, kW$, then the input power will be ........ $kW$.

For an ideal transformer,if $N_S > N_P$,then . . . . . . .

An $AC$ source of internal resistance $10^3 \Omega$ is connected to a transformer. The ratio of the number of turns in the primary to the number of turns in the secondary to match the source to a load resistance of $10 \Omega$ is