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:

The efficiency of a transformer is very high because

$A$ step-down transformer is used on a $1000\,V$ line to deliver $20\,A$ at $120\,V$ at the secondary coil. If the efficiency of the transformer is $80\%$,the current drawn from the line is ......$A$.

$A$ 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 is used to light a $100 \,W$ and $110 \,V$ lamp from a $220 \,V$ mains. If the main current is $0.5 \,A$, the efficiency of the transformer is approximately (in $\%$)

$A$ power transformer is used to step up an alternating $e.m.f.$ of $220\,V$ to $11\,kV$ to transmit $4.4\,kW$ of power. If the primary coil has $1000$ turns,what is the current rating of the secondary (in $,A$)? Assume $100\%$ efficiency for the transformer.