Transmission Of Heat Question 233
Question: Two spheres made of same material have radii in the ratio 1: 2 Both are at same temperature. Ratio of heat radiation energy emitted per second by them is
[MP PMT 2002; MH CET 2004]
Options:
A) 1 : 2
B) 1 : 8
C) 1 : 4
D) 1 : 16
Show Answer
Answer:
Correct Answer: C
Solution:
$ Q=A\varepsilon \sigma T^{4} $
Therefore $ Q\propto A\propto r^{2} $ ($ \because $ T = constant)
$ \Rightarrow \frac{Q _{1}}{Q _{2}}=\frac{r _{1}^{2}}{r _{2}^{2}}={{( \frac{1}{2} )}^{2}}=\frac{1}{4} $
BETA
