A transformer of efficiency $90 \%$ draws an input power of 4 kW . An electrical appliance connected

Question

A transformer of efficiency $90 \%$ draws an input power of 4 kW . An electrical appliance connected across the secondary draws a current of 6 A . The load resistance is:

Professor PC Thomas Classes · Answer

Input power is 4 kW Efficiency is $90 \%$
$$
\begin{aligned}
& 	herefore \quad 	ext { Output power }=0.9 	imes 4 \mathrm{~kW}=3.6 \mathrm{~kW} \
& 3.6 \mathrm{kIV}=i^2 R=36 	imes R \
& 	ext { or } R=\frac{3.6 \mathrm{~kW}}{36}=\frac{3.6 	imes 10^3 \mathrm{~W}}{36} \
& =10^2 \Omega=100 \Omega
\end{aligned}
$$