A heat engine operating between a cold reservoir temperature of 300K and a hot reservoir takes 200J of heat from the hot reservoir and delivers 120J of heat to the cold reservoir in a cycle. The minimum temperature of the hot reservoir is :

Answer 1

as u know .... efficiency=W/Qhot x 100 ............ W=Qhot-Qcold........................ so from here u can get the value of work and put it into the above efficiency equation ......... after getting the answer of efficiency then apply formula ................... efficiency=1-Tcold/Thot x 100