Transmission Of Heat Question 318
Question: A black body of surface area $ 10,cm^{2} $ is heated to $ 127{}^\circ C $ and is suspended in a room at temperature $ 27{}^\circ C $ . The initial rate of loss of heat from the body at the room temperature will be
Options:
A) 2.99 W
B) 1.89 W
C) 1.18 W
D) 0.99 W
Show Answer
Answer:
Correct Answer: D
Solution:
Loss of heat $ \Delta Q=A\varepsilon \sigma (T^{4}-T _{0}^{4})t $
$ \Rightarrow $ Rate of loss of heat $ \frac{\Delta Q}{t}=A\varepsilon \sigma (T^{4}-T _{0}^{4}) $
$ =10\times {{10}^{-4}}\times 1\times 5.67\times {{10}^{-8}}{{{273+127)}^{4}}-{{(273+27)}^{4}}} $ = 0.99 W.
BETA
