An ideal transformer has $100$ turns in the primary and $250$ turns in the secondary. The peak value of the $ac$ input voltage is $28 \, V$. The r.m.s. secondary voltage is nearest to.....$V$

$A$ 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?

$A$ transformer having an efficiency of $90 \%$ is working on a $200 \ V$ and $3 \ kW$ power supply. If the current in the secondary coil is $6 \ A$,the voltage across the secondary coil and the current in the primary coil respectively are:

$A$ small town with a demand of $900 \text{ kW}$ of electric power at $220 \text{ V}$ is situated $20 \text{ km}$ away from an electric power generating station. The two-wire line has a resistance per unit length of $5 \times 10^{-4} \text{ } \Omega \text{ m}^{-1}$. The town gets power from the line through a $45000 \text{ V}$ to $220 \text{ V}$ step-down transformer at a substation in the town. The line power loss in the form of heat is: (in $text{ kW}$)

$A$ power transformer (step-up) with a $1:8$ turn ratio has $60\, Hz, 120\, V$ across the primary; the load in the secondary is $10^4\ \Omega$. The current in the secondary is:

$A$ step-up transformer operates on a $230 \ V$ line and a load current of $2 \ A$. The ratio of primary and secondary windings is $1:25$. Then the current in the primary is (in $A$)