Question

Temp Vs pressure graph of an ideal gas is shown. Then during the process AB.

• A. Internal energy of the gas continuously decreases
• B. Volume of the gas increases
• C. Work done by atmosphere on the gas is + Ve
• D. Temperature is directly proportional to pressure

Answer 1

Answer: (C)

Work done by atmosphere on the gas is + Ve

Answer 2

Volume decreases, so work done by gas is negative two equal parts A and B. Part A has an ideal gas at pressure P₀ and temperature T₀ and in part B is vacuum. A massless spring of force constant k is connected with piston and the wall of the container as shown. Initially spring is unstretched. Gas in chamber A is allowed to expand. Let in equilibrium spring is compressed by x₀. Then –

(1) final pressure of the gas is

(2) work done by the gas is $\frac { 1 } { 2 } \mathrm { kx } _ { 0 } ^ { 2 }$

(3) change in internal energy of the gas is $\frac { 1 } { 2 } \mathrm { kx } _ { 0 } ^ { 2 }$

(4) temperature of the gas is decreased