How does a diffraction grating function?

A diffraction grating functions by separating light into different wavelengths through the process of interference, making option B the correct choice. When light waves encounter the closely spaced lines or slits of the grating, they diffract and spread out in various directions. This diffraction occurs because different wavelengths of light bend at slightly different angles when passing through the grating.

As the light waves overlap and interfere with one another, they create a pattern of bright and dark spots, known as an interference pattern. The angles at which these bright spots occur correspond to specific wavelengths, which allows the diffraction grating to effectively separate light into its constituent colors or spectral components. This principle is widely used in applications like spectrometry, where analyzing the different wavelengths of light can provide information about its source.

The other options do not represent the primary function of a diffraction grating. Amplifying light intensity does not occur through a grating; reflection at a uniform angle pertains more to mirrors, and absorption relates to materials that do not transmit or reflect specific wavelengths, rather than separating them. Thus, the key function of a diffraction grating is the separation of light into its different wavelengths through interference.