NTA Abhyas JEE Main2020PhysicsThermodynamicsPractice
A sample of 2 kg monoatomic helium gas (assumed ideal) is taken through the process A B C and another sample of 2 kg of the same gas is taken through the process A D C . Given that the molecular mass of helium = 4 amu , find the temperature of helium in the state D . [ Take the universal gas constant R = 25 3 J mol - 1 K - 1 ]
Correct answer
240
Step-by-step solution
Number of gram moles of He, n = m M = 2 × 1 0 3 4 = 500 V A = 10m 3 , p A = 5 x 10 4 N/m 2 T A = P A V A n R = ( 10 ) ( 5 × 1 0 4 ) ( 500 ) ( 25 3 )   K = 120   K Similarly, V B = 10m 3 , p B = 10 x 10 4 N/m 2 T B = ( 10 ) ( 10 × 1 0 4 ) ( 500 ) ( 25 3 )   K = 240   K Similarly, V C = 20 m 3 , p C = 10 x 10 4 N/m 2 T C = ( 20 ) ( 10 × 1 0 4 ) ( 500 ) ( 25 3 )   K = 480   K Similarly, V D = 20 m 3 , p D = 5x 10 4 N/m 2 T D = ( 20 ) ( 5 × 1 0 4 ) ( 500 ) ( 25 3 )