A solid cube and a solid sphere of identical material and equal masses are heated to the same temperature and left to cool in the same surroundings. Then,
KVPY 2009, Medium
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(b)
Area of cube is more than that of a sphere for same mass and density.
Cube also have sharp edges that radiates more effectively than a flat surface.
So, rate of cooling for cube is much rapid than sphere. Effect of sharp edges is prominent only at very high
temperatures. So, option $(b)$ is correct.
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