Q. Unsteady state of heat flow occurs in (A) Flow of heat through furnace walls (B) Flow of heat through insulated pipe with constant surface temperature (C) Annealing of castings (D) Flow of heat through refrigerator walls 👁️ Show Answer 💬 Discuss 🔗 Share ⚡Menu ✅ Correct Answer: (C) Annealing of castings