In a step-up transformer,$220 \, V$ is converted into $2200 \, V$. The number of turns in the primary coil is $600$. What is the number of turns in the secondary coil?

In a primary coil,a $5\,A$ current is flowing at $220\,V$. In the secondary coil,a voltage of $2200\,V$ is produced. The ratio of the number of turns in the secondary coil to the primary coil is:

$A$ small town with a demand of $800 \; kW$ of electric power at $220 \; V$ is situated $15 \; km$ away from an electric plant generating power at $440 \; V$. The resistance of the two-wire line carrying power is $0.5 \; \Omega/km$. The town gets power from the line through a $4000-220 \; V$ step-down transformer at a sub-station in the town.
$(a)$ Estimate the line power loss in the form of heat.
$(b)$ How much power must the plant supply,assuming there is negligible power loss due to leakage?
$(c)$ Characterise the step-up transformer at the plant.

The primary and secondary coils of a transformer have $50$ and $1500$ turns respectively. If the magnetic flux $\phi = \phi_0 + 4t$,where $\phi$ is in webers,$t$ is time in seconds and $\phi_0$ is a constant,the output voltage across the secondary coil is......$V$

The coils of a step-down transformer have $500$ and $5000$ turns. In the primary coil, an $AC$ current of $4 \,A$ at $2200 \,V$ is sent. The value of the current and potential difference in the secondary coil is:

$A$ 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......$\%$