An electric motor operation on a $50\;v$ d.c supply draws a current of $12\;A$ . If the efficiency of the motor is $30\%$ , estimate the resistance of the motor .

Question

$\begin{array}{1 1} 30 \;\Omega \\ 0.3\;\Omega \\ 3\;\Omega \\ 0.03\; \Omega \end{array} $