Calorimetry

Step 1: Same material and same mass. Since all three bodies are made of same material and have same mass:
• Density is same
• Heat capacity per unit mass is same
• Total heat to be lost for same temperature fall is same So cooling rate mainly depends on exposed surface area.

Step 2: Law of cooling / radiation idea. Rate of heat loss is proportional to surface area: $ $

Concept: Physics (Thermal Properties) - Stefan's Law and Rate of Radiation.

Step 1: Relate the volumes of the sphere and cube. Given that the volumes are equal ( : $ Q A $