In one complete cycle, a heat engine extracts heat Qh from a thermal reservoir, does work W and does not eject any heat into the environment. This heat engine is impossible because its operation violates:
A
Conservation of energy (1st Law) only
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
2nd Law only
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
C
Both 1st Law and 2nd Law
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
Neither 1st nor 2nd law
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution
The correct option is B2nd Law only This would violate the 2nd Law only. The entropy of the hot reservoir decreases by ΔS=QT. The entropy of the engine did not change (since it returns to its initial state). The entropy of the rest of the universe did not change, since doing pure work does not change entropy.