" The efficiency of heat engine is "

The efficiency of a heat engine is 20% , when the working substance is hydrogen. Its efficiency if hydrogen is replaced by oxygen is

The efficiency of a heat engine if the temperature of the source is 100^(@)C and sink is 27^(@)C is nearly

The efficiency of a heat engine if the temperature of the source is 100^@C and sink is 27^@C is nearly

The efficiency of a heat engine if the temperature of source 127∘ C and that of sink is 27∘ C nearly

The efficiency of a heat engine if the temperature of source 227^(@)C and that of sink is 27^(@)C nearly