• # question_answer In a certain ideal refrigeration cycle, the COP of heat pump is 5. The cycle under identical conditions running as heat engine will efficiency as: A) Zero                             B) 0.20C) 1.00                             D) 6.00

${{(COP)}_{HP}}=\frac{{{T}_{2}}}{{{T}_{1}}-{{T}_{2}}}=5$ $={{\eta }_{H.E}}=\frac{{{T}_{1}}-{{T}_{2}}}{{{T}_{1}}}=\frac{1}{5}=0.2$