Question

Certain substance emits only the wavelengths, ${\lambda }_1,{\lambda }_2,{\lambda }_3$ and ${\lambda }_4$ when it is at a high temperature. When this substance is at a colder temperature, it will absorb only the following wavelengths:

• A. ${\lambda }_1$
• B. ${\lambda }_2$
• C. ${\lambda }_1$ and ${\lambda }_2$
• D. ${\lambda }_1,{\lambda }_2,{\lambda }_3$ and ${\lambda }_4$

Answer 1

The correct option is D ${\lambda }_1,{\lambda }_2,{\lambda }_3$ and ${\lambda }_4$

If a body emits wavelength ${\lambda }_1,{\lambda }_2,{\lambda }_3$ and ${\lambda }_4$ at a high temprtature then at a lower temperature it will absorbs the radiation of same wavelength. This is in accordance with Kirchoff's law.