A hollow copper sphere S and a hollow copper cube C , both of negligible thin walls of same area, ar

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10-2.Transmission of Heat

hard

A hollow copper sphere $S$ and a hollow copper cube $ C$ , both of negligible thin walls of same area, are filled with water at $90°C$ and allowed to cool in the same environment. The graph that correctly represents their cooling is

Solution

(c)$\frac{{d\theta }}{{dt}} = \frac{{\varepsilon A\sigma }}{{mc}}4\theta _0^3\Delta \theta $
For given sphere and cube $\frac{{\varepsilon A\sigma }}{{mc}}4\theta _0^3\Delta \theta $ is constant so for both rate of fall of temperature $\frac{{d\theta }}{{dt}} = $constant

Standard 11

Physics