Question

Consider a solar system with planets that revolve around the sun in circular orbits. The temperature (T) of a planet having no atmosphere situated at a distance r from the sun varies as

• A. $T\propto r^4$
• B. $T\propto r^{4/3}$
• C. $T\propto r^{1/3}$
• D. $T\propto r^{-1/2}$

Answer 1

The correct option is D $T\propto r^{-1/2}$

By Stefen Boltzmans law

$E=\sigma T^4$

$\Rightarrow T\propto E^{1/4}$

also, $E\propto r^{-2}$

$\therefore T\propto r^{-1/2}$

Ans: $D$