$A$ step-down transformer has a $N_{S}$ to $N_{P}$ ratio of $1: 20$. If $8 \, V$ are developed across a $0.4 \, \Omega$ secondary load, the primary current will be: (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?

In a lossless transformer,an alternating current of $2 \ A$ is flowing in the primary coil. The number of turns in the primary and secondary coils are $100$ and $20$ respectively. The value of the current in the secondary coil is.......$A$

How much current is drawn by the primary coil of a transformer,which steps down $220 V$ to $55 V$ to operate a device with an impedance of $275 \Omega$ (in $A$)?

$A$ transformer is employed to reduce $220\, V$ to $11\, V$. The primary draws a current of $5\, A$ and the secondary $90\, A$. The efficiency of the transformer is......$\%$

$A$ transformer consists of $500$ turns in the primary coil and $10$ turns in the secondary coil with a load of $10\, \Omega$. Find the current in the primary coil when the voltage across the secondary coil is $50\, V$. (in $A$)