Question

A system goes from A to B by two different paths in the P-V diagram as shown in figure.

Heat given to the system in path 1 is 1100 J, the work done by the system along path 1 is more than path 2 by 150 J. The heat exchanged by the system in path 2 is.

• A. 800 J
• B. 750 J
• C. 1050 J
• D. 950 J

Answer 1

Answer: (D)

950 J

Answer 2

The change in internal energy of system will be same for both paths 1 and 2.

Along path, $\Delta Q_{1} = \Delta U + \Delta W_{1}$ ….. (i)

Along path2, $\Delta Q_{2} = \Delta U + \Delta W_{2}$ ….. (ii)

Subtract (ii) from (i), we get

Or $\Delta Q_{1} - \Delta Q_{2} = \Delta W_{1} - \Delta W_{2}

}{\Delta Q_{2} = 1100 - 150 = 950J}$$