A sphere of ice at 0 ∘ C having initial radius R is placed in an environment having ambient temperature greater than 0 ∘ C . The ice melts uniformly so that its shape remains spherical. After a time t

Question

A sphere of ice at 0 ∘ C having initial radius R is placed in an environment having ambient temperature greater than 0 ∘ C . The ice melts uniformly so that its shape remains spherical. After a time t the radius has reduced to r . Assuming that the rate of heat absorption is proportional to the surface area of the sphere at any moment, which graph best depicts r ( t ) ?

TestHub · Accepted Answer

Heat input rate is proportional to 4 π r 2 Melting requires Q ˙ ​ = − ρ L f ​ 4 π r 2 d t d r ​ Thus d r / d t is a negative constant; radius decreases linearly.

Physics - Heat & Thermo Question with Solution | TestHub

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