A sphere has a surface area of `1.0 m^(2)` and a temperature of 400 K and the power radiated from it is 150 W. Assuming the sphere is black body radiator. The power in kilowatt radiated when the area expands to `2.0 m^(2)` and the temperature changes to 800 K

Options

A. 6.2
B. 9.6
C. 4.8
D. 16

Answer

C

Explanation

`p propto AT^(4)`
Area and temperature both are doubled. Hence, power will become `(2)^(5)` or 32 times.
`therefore P^(') = 32P = (32 xx 150)/(1000) kW = 4.8 kW`