$A$ power transmission line feeds input power at $2300\; V$ to a step-down transformer with its primary windings having $4000$ turns. What should be the number of turns in the secondary in order to get output power at $230\; V$?

$A$ current of $4 \text{ A}$ is flowing at $230 \text{ V}$ in the primary coil of a transformer. If the voltage produced in the secondary coil is $2300 \text{ V}$ and $40\%$ of power is lost, then the current in the secondary will be (in $\text{ A}$)

$A$ 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 a transformer,the turns ratio is $3$ and its efficiency is $0.75$. The current flowing in the primary coil is $2 \,A$ and the voltage applied to it is $100 \,V$. Then the voltage and the current flowing in the secondary coil are ... respectively.

The primary and secondary coils of a transformer have $50$ and $1500$ turns respectively. If the magnetic flux $\phi = \phi_0 + 4t$,where $\phi$ is in webers,$t$ is time in seconds and $\phi_0$ is a constant,the output voltage across the secondary coil is......$V$

$A$ transformer is used to step up an alternating e.m.f. of $220 \ V$ to $4.4 \ kV$ to transmit $6.6 \ kW$ of power. The primary coil has $1000$ turns. The current rating of the secondary coil is (Transformer is ideal): (in $A$)