Question

Two strips of material, A and B, are identical, except that they have emissivities of 0.4 and 0.6, respectively. The strips are heated to the same temperature and have a red glow. A brighter glow would signify that more energy per second is being radiated. Which strip has a brighter glow?

A. Both strips would have the same brightness.
B. Strip A
C. Strip B.

Answer 1

C. Strip B.

Step-by-step explanation:

Every body which has certain temperature emit radiations. Hotter bodies emit radiations of shorter wavelength whereas less hotter bodies emit radiations of longer wavelengths.

Moreover, bodies with higher values of emissivity emit more wavelength of higher intensities and than bodies with lower emissivity. Here in this case emissivity of B is greater than emissivity of A (0.6>0.4). Therefore, strip B will glow more brighter than strip A.