When light passes through a prism, it undergoes refraction, separating into its component colors due to varying speeds in the different wavelengths. This dispersion reveals the spectrum, showcasing distinct hues.
White light is passed through a prism to yield a spectrum. (a) The ray of which colour will show the maximum angle of deviation and which one will show the least angle of deviation? (b) A blue-coloured ray is passed through a glass prism. What will be the colour of the emergent ray? Justify your answer.
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(a) When white light is passed through a prism, it disperses into its component colors due to the phenomenon of dispersion. The angle of deviation for each color is different because each color has a different wavelength, and the refractive index of the prism varies with wavelength.
The color that undergoes the maximum angle of deviation is violet. This is because violet light has the shortest wavelength among the colors in the visible spectrum, and it experiences the greatest change in direction when passing through the prism.
The color that undergoes the least angle of deviation is red. Red light has the longest wavelength among the colors in the visible spectrum, and it experiences the least change in direction when passing through the prism.
(b) When a blue-coloured ray is passed through a glass prism, it undergoes dispersion, and the emergent ray will consist of various colors. The color of the emergent ray will include blue along with other colors of the spectrum. This is because the blue light will be bent or refracted more than the other colors due to its shorter wavelength. The specific color composition of the emergent ray will depend on the dispersion characteristics of the prism.