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 impedance of the device is\

Professor PC Thomas Classes · Answer

Input is 4 kW . Efficiency is $90 \%$\ $	herefore$ output efficiency $=0.9 	imes 4 \mathrm{~kW}=3.6 \mathrm{~kW}=\mathrm{i}^{2} \mathrm{R}=$ $=36 	imes \mathrm{R}$\ $=\frac{3.6 \mathrm{~kW}}{36}=\frac{3.6 	imes 10^{3} \mathrm{~W}}{36}=10^{2} \Omega=100 \Omega$\