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A small-blackened solid copper sphere of...

A small-blackened solid copper sphere of radius 2.5 cm is placed in an evacuated chamber. The temperature of the chamber is maintained at `100^(@)C`. At what rate energy must be supplied to the copper sphere to maintain its temperature at `110^(@)C`? (Take Stefan's constant `sigma` to be `5.76xx10^(-8) J s^(-1) m^(-2) K^(-4)` and treat the sphere as blackbody.)

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