4. Two identical containers A and B with frictionless pistons contain the same ideal gas at the same temperature and the same volume V.

The mass of the gas in A is m_B and that in B  is . The gas in each cylinder is now allowed to expand isothermally to the same final volume 2V. The changes in the pressure in A and B are found to be ΔP and 1.5 ΔP  respectively. Then

(a)    4m_A = 9m_B                    (b) 2m_A = 3m_B

(c)   3m_A = 2m_B                          (d) 9m_A = 3m_B

Ans. c