Transmission Of Heat Question 244
Question: A black body radiates energy at the rate of 1 ´ 105 J / s ´m2 at temperature of 227o C. The temperature to which it must be heated so that it radiates energy at rate of 1 ´ 109J/sm2, is
[DPMT 2004]
Options:
A) 5000 K
B) 5000 oC
C) 500 K
D) 500 oC
Show Answer
Answer:
Correct Answer: A
Solution:
$ \frac{E _{2}}{E _{1}}={{( \frac{T _{2}}{T _{1}} )}^{4}} $
Therefore $ \frac{T _{2}}{T _{1}}={{( \frac{E _{2}}{E _{1}} )}^{1/4}}={{( \frac{10^{9}}{10^{5}} )}^{1/4}}=10 $
Therefore $ T _{2}=10T _{1}=10\times (273+227)=5000,K $
BETA
