Sign convention of heat and work

1. Heat (q)
    Case I:
            When heat is absorbed by the system, q = +ve.

    Case II:
             When heat is released by the system, q = -ve.

2. Work (w)
    Case I: (Work of Expansion)
             When work is done by the system, w = +ve.

    Case II: (Work of Compression)
             When work is done on the system, w = -ve.

Have a question? Ask us in our discussion forum.