Solved UPSC CDS/OTA Question
A solved UPSC CDS/OTA PYQ — decoded step-by-step.
Solve it the standard way once — then learn the shortcut.
Q · Heat and ThermodynamicsMedium · 45s
A heat engine absorbs 2000 J from the hot reservoir and rejects 1200 J to the sink. Its efficiency is:
TopicHeat and Thermodynamics
Question Typemultiple choice
DifficultyMedium
Marking+1 / −0.33
Test Duration30 min
Step-by-Step Solution
The complete worked solution.
Every step explained — no skipped algebra.
Efficiency η = (Q₁ - Q₂)/Q₁ = (2000-1200)/2000 = 0.4 = 40%.
Final Answer: Option B — 40%