The rate of cooling of an object is primarily governed by its surface area to volume ratio and the material's properties (like emissivity and conductivity). Objects lose heat to the surroundings through radiation, convection, and conduction. For a given material and initial temperature difference, a higher surface area to volume ratio (SA/V) leads to a faster rate of heat loss per unit volume, and thus faster cooling.
A hollow sphere of radius R, a hollow cube of side R and a thin circular plate of radius R, made up of the same material, are all heated to 20°C above room temperature. When left to cool in the room, which of them will reach the room temperature first?
Asked in UPPCS Prelims 2002 · Topic: Heat and Thermodynamics (Modes of Heat Transfer (Conduction, Convection, Radiation))
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