$A$ transformer is used to

The core of a transformer is made up of:

The quantity that remains unchanged in a transformer is:

An ideal transformer converts $220 \ V$ $AC$ to $3.3 \ kV$ $AC$ to transmit a power of $4.4 \ kW$. If the primary coil has $600$ turns,then the alternating current in the secondary coil is:

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 $.........\,m\Omega$.

Why is a soft iron core used in a transformer?