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.