$A$ transformer is used to light a $100 \,W-110 \,V$ lamp from a $220 \,V$ mains. If the main current is $0.5 \,A$, the efficiency of the transformer is: (in $\%$)

For an ideal transformer with primary voltage $E_{p} = 1000 \, V$ and primary current $I_{p} = 50 \, A$,if the secondary voltage is $220 \, V$ and it supplies power to $80$ houses,what is the equivalent resistance of the secondary circuit (in $\Omega$)?

$A$ power transmission line feeds input power at $2300 \, V$ to a step-down transformer with its primary windings having $4000$ turns. The output power is delivered at $230 \, V$ by the transformer. If the current in the primary of the transformer is $5 \, A$ and its efficiency is $90 \%$,the output current would be......$A$.

The output power in a step-up transformer used in practice is . . . . . .

$A$ step-down transformer is connected to a $2400\,V$ line, and $80\,A$ of current is found to flow in the output load. The ratio of the turns in the primary and secondary coil is $20:1$. If the transformer efficiency is $100\%$, then the current flowing in the primary coil will be......$A$.

$A$ $60\, W$ load is connected to the secondary of a transformer whose primary draws line voltage. If a current of $0.54\, A$ flows in the load,what is the current in the primary coil? Comment on the type of transformer being used.