The primary and secondary voltage of an ideal step-down transformer is $200 \,V$ and $25 \,V$ respectively. The secondary is connected to a device,which draws a current of $2 \,A$. The current in the primary is (in $\,mA$)

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?

Which of the following statements is correct regarding a step-down transformer?

The output voltage of a transformer connected to a $220 \, V$ line is $1100 \, V$ at a $1 \, A$ current. Its efficiency is $100 \%$. The current coming from the line is ........ $A$.

$1\, MW$ 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: $\rho_{Cu} = 1.7 \times 10^{-8}\, \Omega \cdot m$.

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