Question
Question: Radiation from a black body at the thermodynamic temperature T<sub>1</sub> is measured by a small de...
Radiation from a black body at the thermodynamic temperature T1 is measured by a small detector at distance d1 from it. When the temperature is increased to T2 and the distance to d2, the power received by the detector is unchanged. What is the ratio d2/d1?
A
T2/T1
B
(T2/T1)2
C
(T1/T2)2
D
(T2/T1)4
Answer
(T2/T1)2
Explanation
Solution
P µ T4/r2