$A$ distribution transformer with an efficiency of $90 \%$ supplies power to a colony of $10$ homes. All the $10$ homes have an electrical oven running at the same time,each drawing $20 \ A$ current from $220 \ V$ lines. The power dissipated as heat in the transformer is: (in $kW$)

$A$ step-up transformer has a transformation ratio of $3:2$. What is the voltage in the secondary coil if the voltage in the primary coil is $30\, V$?

In an ideal transformer,the turns ratio is $\frac{N_p}{N_S} = \frac{1}{2}$. The ratio $V_s : V_p$ is equal to (the symbols carry their usual meaning):

$A$ 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$)

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

In a transformer,$220 \ V$ $AC$ voltage is increased to $2200 \ V$. If the number of turns in the secondary coil is $2000$,then the number of turns in the primary coil will be: