In a step-up transformer,the transformation ratio is $4:1$. If a Leclanche cell having an $EMF$ of $1.5 \ V$ is connected to the primary coil of the transformer,then the voltage obtained across its secondary coil is . . . . . . .

If a step-up transformer has a turn ratio of $5$,a frequency of $50 \, Hz$,the root mean square $(RMS)$ value of the potential difference on the primary is $100 \, V$,and the resistance of the secondary winding is $500 \, \Omega$,then the peak value of the voltage in the secondary winding will be (the efficiency of the transformer is $100 \%$).

Why is a soft iron core used in a transformer?

$A$ 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 $40,000-220 \; V$ 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.
(Neglect,as before,leakage losses). Hence,explain why high-voltage transmission is preferred?

$A$ step-down transformer is connected to a $2400 \, V$ line, and $80 \, A$ of current is found to flow in the output load. The ratio of the turns in the primary and secondary coil is $20 : 1$. If the transformer efficiency is $100\%$, then the current flowing in the primary coil will be: (in $A$)

In an ideal step-down transformer, out of the following quantities, which quantity increases in the secondary coil?