Thermodynamics Question 315
Question: An ideal monoatomic gas is confined in a cylinder, fitted with piston, which is connected to spring . The gas is heated by a-small electric heater until the piston moves out slowly by 0.1 m. Find the work done by the gas. Spring constant = 8000 N/m,-piston area $ =8\times {{10}^{-3}}{{\text{m}}^{2}} $ atmospheric pressure $ =10^{5}Pa $ .
Options:
A) 40 J
B) 80 J
C) 120 J
D) 60 J
Show Answer
Answer:
Correct Answer: C
Solution:
[c]Work done $ =\int _{0}^{x _{0}}{p _{0}Axdx}+\frac{kx _{0}^{2}}{2} $
$ =p _{0}Ax _{0}+\frac{kx _{0}^{2}}{2}=80+40=120J $
where p = pressure of gas, $ p _{0}= $
atmospheric pressure k = spring constant $ x _{0}= $ compression in spring.
