Arun
Last Activity: 6 Years ago
Dear Lakshya
(i) As thermal expansion of isotropic solids is similar to true photographic enlargement, the expansion of a cavity is same as if it were a solid body of the same material i.e. ∆V = $\gamma$V ∆T. As here V, $\gamma$ and ∆T are same for both solid and hollow spheres, so the expansions of both will be equal.
(ii) If same amount of heat is given to the two spheres, then due to lesser mass, rise in temperature of hollow sphere will be more (as ∆T = Q/Mc) and hence the expansion will bemore as ∆V = $\gamma$V ∆T.
Regards
Arun(askIITians forum expert)