# How is efficiency of heat engine cycle given?- Thermodynamics

Q.  Efficiency of heat engine cycle is the ratio of
- Published on 19 Aug 15

a. total heat input to the cycle (Qin) to net work output of the cycle (Wnet)
b. net work output of the cycle (Wnet) to total heat input to the cycle (Qin)
c. net work output of the cycle (Wnet) to heat rejected from the system (Qout)
d. none of the above

ANSWER: total heat input to the cycle (Qin) to net work output of the cycle (Wnet)

In heat engine cycle, the heat is transferred to the system and work is transferred from the system. The main function of heat engine is to produce work output continuously by consuming heat energy given to the system. So the net work (Wnet) and heat supplied (Qin) to the system are taken into account. The net work output is the difference between work produces in the process and the work input required to take the system to initial state. In stem power plant, net work output is,
Turbine Work (WT) – Pump Work (WP)
Therefore, the efficiency of heat engine cycle is the ratio of total heat input to the cycle (Qin) to net work output of the cycle (Wnet).

#### Discussion

• Mudasir ahmad mir   -Posted on 15 Apr 18
Rt answer is work done/heat supplied
• Huzaifa   -Posted on 29 Jan 18
Correct answer is Efficiency=Work output/Heat input
• sarat babu mulpur   -Posted on 16 Jun 17
wrng answer efficiency output by input
• wrng ans   -Posted on 16 Jun 17
wrng ans
• srinivasulu.v   -Posted on 21 May 17
efficiency of any machine = output/input = work produced/heat input
• Anurag   -Posted on 17 Aug 16
Wrong ans efficient =work/qin

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