Chapter 19, Problem 45A

To determine

The color of visible light which produces a bright line for the given specifications.

Answer to Problem 45A

Violet color will produce a bright line for the given specifications.

Explanation of Solution

Introduction:

Diffraction grating is an optical component that comprises of a surface ruled with an equidistant, closely spaced, parallel lines. These lines in the grating are opaque and the spacing between the lines acts as a number of closely placed slits. They can disperse the light beam passing through it and produce a spectrum of light by the principle of diffraction. Gratings are able to produce high resolution spectral lines and hence they are used in high resolution spectrometers. The diffraction through the grating depends on the wavelength of light and also on the spacing between the lines in the grating.

The color having a smallest wavelength will produces a bright line closest to the central bright band in the diffraction pattern. In the visible light, violet color has the smallest wavelength compared to all other colors. Hence violet color will produce a bright line closest to the central bright band in the diffraction pattern that is produced by a given diffraction grating when visible light incident on it.