Thermodynamics Question 224
Question: When an ideal monoatomic gas is heated at constant pressure, the fraction of the heat energy supplied which increases the internal energy of the gas is
Options:
A) 2/5
B) 3/5
C) 3/7
D) 5/7
Show Answer
Answer:
Correct Answer: B
Solution:
[b] By first law, $ \Delta Q=\Delta U+\Delta W $
$ =\frac{f}{2}nRT+P\int _{{}}^{{}}{dV=\frac{f}{2}}nRT+PV $
$ \Delta Q=\frac{f}{2}nRT+nRT=\frac{3}{2}nRT+nRT=\frac{5}{2}nRT $
$ \therefore \text{Fraction=}\frac{( 3/2 )nRT}{( 5/2 )nRT}=\frac{3}{5} $
