Q.

An ideal gas expands isothermally from 10-3m3 to 10-2m3 at 300 K against a constant pressure of 105N m-2. The work done on the gas is    [2019]
 

1 +270 kJ  
2 -900 J  
3 +900 kJ  
4 -900 kJ  

Ans.

(2)

w=-PdV=-P(V2-V1)

=-105Nm-2(10-2-10-3)m3=-105Nm-2(9×10-3)m3

=-9×102Nm=-900J                                         (1J=1Nm)