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A copper ball of diameter d was placed i...

A copper ball of diameter d was placed in an evacuated vessel whose walls are kept at the absolute zero temperature. The initial temperature of the ball is `t_(0)`. Assuming the surface of the ball to be absolutely black, find how soon its temperature decreases `eta` times. Take specific heat of copper c, density of copper `rho` and emissivity e.

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To solve the problem, we need to determine how long it takes for the temperature of a copper ball to decrease to \(\frac{T_0}{\eta}\) when placed in an evacuated vessel at absolute zero temperature. We will use the principles of heat transfer through radiation. ### Step-by-Step Solution: 1. **Identify the Parameters**: - Let the diameter of the copper ball be \(d\). - The radius \(r\) of the ball is \(\frac{d}{2}\). - The initial temperature of the ball is \(T_0\). ...
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