$A$ 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$)

In a transformer,the core is made of soft iron to reduce:

$A$ transformer may be used to provide maximum power transfer between two $AC$ circuits that have different impedances $Z_1$ and $Z_2$. The ratio of turns $N_1/N_2$ needed to meet this condition is given by :-

An ideal transformer is used to step up an alternating e.m.f. of $220 \,V$ to $4.4 \,kV$ to transmit $6.6 \,kW$ of power. The primary coil has $100$ turns. What is the current rating of the 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?

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