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?
✓ Correct answer: c) Sphere
ExplanationThe rate at which an object cools depends on its surface area-to-volume ratio and temperature difference with the surroundings.A higher surface area-to-volume ratio allows more heat to be dissipated into the surroundings, leading to faster cooling.The sphere has the largest surface area compared to the cube and circular plate.The larger the surface area, the more heat can be radiated or transferred to the surroundings, which leads to a faster cooling rate.The sphere cools faster than the circular plate and cube for the same radius.The more heat the sphere can radiate, the quicker it will reach room temperature compared to objects with smaller surface areas.Note: Here, we can ignore the impact of volume as the sphere, disc or cube all are hollow with negligible thickness.246
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