A) \[{{10}^{4}}\]
B) 625
C) 256
D) 16
Correct Answer: B
Solution :
From Stefan?s law, if the emissive power of a body at absolute temperature T be e, then the energy emitted by its unit area per second is \[\sigma {{T}^{4}}\times e\], also if A is the surface area of the body, then \[E=\sigma {{T}^{4}}\times eA\] when \[\operatorname{R}' =100\,\,R\] and \[T'=\frac{T}{2}\], then energy emitted is \[E'\propto 4\pi {{(100\,\,R)}^{2}}{{\left( \frac{T}{2} \right)}^{4}}\] \[\propto {{\left( \frac{100}{4} \right)}^{2}}\,\,\times 4\pi \,{{R}^{2}}{{T}^{4}}\] \[\therefore \,\,\,\,\,\,E'={{\left( \frac{100}{4} \right)}^{2}}\times E\] \[\therefore \,\,\,\,\,\,\,\,\,\frac{E'}{E}=625\]
You need to login to perform this action.
You will be redirected in
3 sec
