A body has a black spot on it. When the body | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(C) According to Kirchhoff's law of radiation,the ratio of emissive power $(e)$ to the absorptive power $(a)$ for a body at a given temperature and wa

Vedclass · Accepted Answer

Kirchhoff's law

Vedclass · Answer

(C) According to Kirchhoff's law of radiation,the ratio of emissive power $(e)$ to the absorptive power $(a)$ for a body at a given temperature and wavelength is constant and equal to the emissive power of a perfectly black body at that temperature. Mathematically,$\frac{e}{a} = E_{\lambda}$,where $E_{\lambda}$ is the emissive power of a black body. This implies that $e \propto a$. $A$ black spot on a body has a higher absorptive power $(a \approx 1)$ compared to the rest of the surface. Since it is a better absorber,it is also a better emitter of radiation at high temperatures. Therefore,when the body is heated and placed in a dark room,the black spot emits more radiation and appears to glow more brightly. Thus,the correct option is $C$.

$A$ body has a black spot on it. When the body is heated and taken into a dark room,the black spot glows more brightly. This can be explained by which of the following?

Similar Questions

In which process is the rate of transfer of heat maximum?

The spectrum of black body radiation is a

Why are the bottom layers of cooking vessels kept black in color?

When the bulb is switched on,what happens to the level of alcohol on the $X$ side?

Compared to a white-skinned person,what does a dark-skinned person experience?

Vedclass Test Series

Exam Paper Generator

Online Exam Module