Chapter 12: Thermodynamics
• ∆U = Q - W
• χ = Cv/Cp
• Efficiency η = 1 - T₂/T₁ (Carnot)
Q1. Find the efficiency of a Carnot engine operating between 500K and 300K.
Solutionη = 1 - T₂/T₁ = 1 - 300/500 = 0.4 = 40%
Q2. 500 J of work is done on a gas while 200 J of heat escapes. Find change in internal energy.
Solution∆U = Q - W = -200 - (-500) = 300 J
(W is negative because work is done on gas)