Question

A heat engine is designed to do work. This is possible only if certain relationships between the heats and temperatures at the input and output hold true. Which of the following sets of statements must apply for the heat engine to do work?
(A) Qh < Qc and Th < Tc
(B) Qh > Qc and Th < Tc
(C) Qh < Qc and Th > Tc
(D) Qh > Qc and Th > Tc

Answer 1

Answer:d

Explanation:

Heat engine is a device which perform work when we supplied heat from a high temperature thermal reservoir(source) and heat is rejected in low temperature reservoir(sink).

for ideal engine we consider temperature of source and sink remain constant irrespective of how much heat is extracted or supplied to them

if $Q_h=$heat supplied

$Q_c=$heat rejected

$T_h=$high temperature reservoir

$T_c=$low temperature reservoir

For proper working

$Q_h>Q_c$ and $T_h>T_c$