A refrigerator extracts 600 J from the cold compartment and rejects 800 J to the room. Its coefficient of performance is:

1. Work done on the refrigerant W = Q₂ − Q₁ = 800 − 600 = 200 J. 2. COP for a refrigerator = Q₁ / W (heat removed per joule of work). 3. COP = 600 / 200 = 3.0. 4. Higher COP means better refrigerator. Real fridges: COP ≈ 2–4. _Source: syllabus Physics Ch 11, §11.11 Refrigerators and Heat Pumps_