The power `P` is received by a surface at temperature `T_(0)K` from a small sphere at temperature

Options

A. `T(T gt gt T_(0))` and at a distance `'d'`. If both `'T'` and `'d'` are doubled, then power received by surface will become
B. `P`
C. `2P`
D. `4P`

Answer

A

Explanation

(c) Radiation `prop(T^(4))/(d^(2))`
`Pprop(T_(0)^(2))/(d_(0)^(2))`
When `T` and `d` are doubled
`p'prop((2)^(4)T_(0)^(4))/(2^(2)d_(0)^(2)) prop (4T_(0)^(4))/(d_(0)^(2))prop 4P`
Therefore power received by surface will become `4P`