Question

A gas is confined to a vertical cylinder by a piston of mass 2 kg and radius 1 cm. When 5J of

heat are added, the piston rises by 2.4 cm. Find: (a) the work done by the gas; (b) the change

in its internal energy. Atmospheric pressure is 105

Pa.​

Answer 1

Answer:

a)   0.753 J

b) 4.247 J

Explanation:

Given:  mass 2 kg and radius 1 cm. When 5 J of

heat are added, the piston rises by 2.4 cm

(a) Work done W = PΔV

Change in volume ΔV = πr^2 h = π x (.01)^2 x .024 =7.53×10^(-6)m^3

Pressure is 10^5 Pa

The,$W=10^5\times7.53\times10^-(6)=0.753J$

W = 0.753 J

(b) Change in internal energy  = heat added - energy lost in work = 5 J -0.753 J = 4.247 J