a
\(\eta = \frac{{{\rm{output}}\,{\rm{power}}}}{{{\rm{input}}\,{\rm{power}}}} = \frac{{{E_s}{I_s}}}{{{E_p}{I_p}}}\)

==> \(\frac{{80}}{{100}} = \frac{{200 \times {I_s}}}{{4 \times {{10}^3}}}\)

==> \({I_S} = \frac{{80}}{{100}} \times \frac{{4 \times 1000}}{{200}} = 16A\)

\({E_p}{I_p} = 4KW\)

==>\({I_p} = \frac{{4 \times {{10}^3}}}{{100}} = 40A\)