Ask Questions, Get Answers

Want to ask us a question? Click here
Home  >>  JEEMAIN and AIPMT  >>  Physics  >>  Class11  >>  Thermodynamics
0 votes

A blackbody of surface area $\;100 cm^{2}\;$ is placed inside an enclosure . The enclosure has a constant temperature at $\;127^{0}C\;$ & the blackbody is maintained at $\;227^{0}C\;$ by heating it electrically . If $\;\sigma=6 \times 10^{-8} Wm^{-2}K^{-4}\;$ , electric power needed to maintain the temperature

$(a)\;12W\qquad(b)\;22W\qquad(c)\;32 W\qquad(d)\;24 W$

Can you answer this question?

1 Answer

0 votes
Answer : 22 W
Explanation :
Area , $\;A = 10^{-2} m^{2}$
$T_{1}=227^{0}C=500 K$
Radiation emitted at $\;A \sigma T_{1}^{4}\;$
Radiation absorbed at $\;A \sigma T_{2}^{4}$
Therefore , The power needed = $\; A \sigma(T_{1}^{4}-T_{2}^{4})$
$=10^{-2}\times 6 \times 10^{-8} ((500)^{4}-(400)^{4})W$
$=2.214 \times 10^{11-10}W$
$=22.14 W$
answered Mar 13, 2014 by yamini.v

Related questions

Ask Question
student study plans
JEE MAIN, CBSE, AIPMT Mobile and Tablet App
The ultimate mobile app to help you crack your examinations
Get the Android App