Question

Consider the following statements:

1. Absorptivity depends on wave length of incident radiation waves

2. Emissivity is dependent on wave length of incident radiation waves

Which of the above statements is/are correct?
1. 1 only
2. 2 only
3. Both 1 and 2
4. Neither 1 nor 2

Answer 1

Correct Answer - Option 3 : Both 1 and 2

Explanation:

• The absorptivity is the amount of radiation absorbed by a surface compared to what is absorbed by a black body.
• Emissivity is defined as the ratio of the energy radiated from a material's surface to that radiated from a perfect emitter, known as a blackbody, at the same temperature and wavelength and under the same viewing conditions.
• Both emissivity and absorptivity depend on the wavelength of incident radiation.
• The emissivity at a certain wavelength is called spectral emissivity. This is applicable for the real surface.