Concepts Of Physics MCQ Edition [Volume 2]PhysicsKinetic Theory of Gases
A cylindrical tube of length 30 cm is partitioned by a tight-fitting separator, as shown in the figure. The separator can freely slide along the tube and is very weakly conducting. The two parts of the vessel are filled with ideal gases. Initially, the temperatures in parts A and B are 400 K and 100 K , respectively, and the separator slides to the momentary equilibrium position indicated. Determine the final equilib
Options
- A10 cm from the left end
- B15 cm from the left end
- C25 cm from the left end
- D20 cm from the left end
Correct answer
A. 10 cm from the left end
Step-by-step solution
At the momentary equilibrium, the pressures in both parts are equal. Let this pressure be P and the cross-sectional area of the tube be S . Using the ideal gas equation PV = nRT , the number of moles in part A and part B are: n_A = P(20S) R(400) n_B = P(10S) R(100) The ratio of the number of moles is: n_A n_B = 20/400 10/100 = 1/20 1/10 = 1 2 After a long time, the system reaches thermal equilibrium because the separator is weakly conducting. The final temperatures in both parts will be equal, say T . Since the sep