A black metal foil is warmed by radiation from a small sphere at temperature T and at a distance d . It is found that the power received by the foil is P . If both the temperature and the distance are

Question

A black metal foil is warmed by radiation from a small sphere at temperature $T$ and at a distance $d$ . It is found that the power received by the foil is $P$ . If both the temperature and the distance are doubled, the power received by the foil will be:

Options:

Answer:

B

Solution:

The power $\propto \frac{T ^{4}}{d ^{2}}$ . The factor is $\frac{2 ^{4}}{2 ^{2}} = 4$ . B.

TestHub · Accepted Answer

The power ∝ d 2 T 4 ​ . The factor is 2 2 2 4 ​ = 4 . B.

Physics - Heat & Thermo Question with Solution | TestHub

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