Transmission Of Heat Question 214
Question: A body radiates energy $ 5W $ at a temperature of $ 127^{o}C $ . If the temperature is increased to $ 927^{o}C $ , then it radiates energy at the rate of
[MP PET 1994;BHU 1995; CPMT 1998; AFMC 2000]
Options:
A) $ 410W $
B) $ 81\ W $
C) $ 405\ W $
D) $ 200\ W $
Show Answer
Answer:
Correct Answer: C
Solution:
Rate of energy $ \frac{Q}{t}=P=A\varepsilon \sigma T^{4} $
Therefore $ P\propto T^{4} $
Therefore $ \frac{P _{1}}{P _{2}}={{( \frac{T _{1}}{T _{2}} )}^{4}} $
$ ={{( \frac{927+273}{127+273} )}^{4}} $
$ \Rightarrow P _{1}=405\ W $
BETA
