$A$ transformer having an efficiency of $90 \%$ is working on a $200 \ V$ and $3 \ kW$ power supply. If the current in the secondary coil is $6 \ A$,the voltage across the secondary coil and the current in the primary coil respectively are:

$A$ 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:

$1\, MW$ power is to be delivered from a power station to a town $10\, km$ away. One uses a pair of $Cu$ wires of radius $0.5\, cm$ for this purpose. Calculate the fraction of ohmic losses to power transmitted if
$(a)$ power is transmitted at $220\, V$. Comment on the feasibility of doing this.
$(b)$ a step-up transformer is used to boost the voltage to $11000\, V$,power is transmitted,then a step-down transformer is used to bring voltage to $220\, V$.
Given: $\rho_{Cu} = 1.7 \times 10^{-8}\, \Omega \cdot m$.

$A$ transformer has $120$ turns in the primary coil and carries $5 \text{ A}$ current. Input power is $1 \text{ kW}$. To have $560 \text{ V}$ output, the number of turns in the secondary coil will be:

$A$ step-down transformer is connected to a main supply of $200\,V$ to operate a $6\,V$,$30\,W$ bulb. The current in the primary coil is.....$A$

$A$ transformer has an efficiency of $80 \%$. The input power to the primary coil is $4 \text{ kW}$ at a voltage of $100 \text{ V}$. If the secondary voltage is $200 \text{ V}$,what are the primary and secondary currents,respectively?