Two spheres of different materials one with d | vedclass

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Question

(d) $Q = \frac{{KA\,(\Delta 	heta )t}}{l}$

$Q$ and $\Delta 	heta $ are same for both spheres hence

$K \propto \frac{l}{{At}} \propto \frac{l}{

Vedclass · Accepted Answer

$1:25$

Vedclass · Answer

(d) $Q = \frac{{KA\,(\Delta 	heta )t}}{l}$

$Q$ and $\Delta 	heta $ are same for both spheres hence

$K \propto \frac{l}{{At}} \propto \frac{l}{{{r^2}t}}$ ==> $\frac{{{K_{{m{larger}}}}}}{{{K_{{m{smaller}}}}}} = \frac{{{l_l}}}{{{l_s}}} 	imes {\left( {\frac{{{r_s}}}{{{r_l}}}} ight)^2} 	imes \frac{{{t_s}}}{{{t_l}}}$. It is given that ${r_l} = 2{r_s},$ ${l_l} = \frac{1}{4}{l_s}$ and ${t_1} = 25$min, ${t_s} = 16$min.

==> $\frac{{{k_{{m{larger}}}}}}{{{k_{{m{smaller}}}}}} = \left( {\frac{1}{4}} ight){\left( {\frac{1}{2}} ight)^2} 	imes \frac{{16}}{{25}} = \frac{1}{{25}}$

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