$A$ step-down transformer transforms $220 \text{ V}$ to $11 \text{ V}$. If the currents in the primary and secondary coils are $5 \text{ A}$ and $90 \text{ A}$ respectively,the efficiency of the transformer is: (in $\%$)

Write two types of transformer.

An ideal transformer with a purely resistive load operates at $12\,kV$ on the primary side. It supplies electrical energy to a number of nearby houses at $120\,V$. The average rate of energy consumption in the houses served by the transformer is $60\,kW$. The value of the resistive load $(R_s)$ required in the secondary circuit will be $.........\,m\Omega$.

$A$ step-down transformer is used to reduce the main supply from $V_1$ volt to $V_2$ volt. The primary coil draws a current $I_1$ $A$ and the secondary coil draws $I_2$ $A$. $(I_1 < I_2)$. The ratio of input power to output power is

The turn ratio of a transformer is given as $2 : 3$. If the current through the primary coil is $3 \, A$,calculate the current through the load resistance (secondary coil). (in $, A$)

If a transformer of an audio amplifier has an output impedance of $8000 \ \Omega$ and the speaker has an input impedance of $8 \ \Omega$,what should be the ratio of the primary to secondary turns of this transformer connected between the amplifier output and the loudspeaker?