Answer option 3 is correct: Violet light bends the most when a light beam falls on a triangular glass prism. This is because the refractive index of glass for violet light is greatest.
When light passes through a medium (in this case, glass), it changes direction due to the change in speed caused by the interaction between the light and the medium. This phenomenon is called refraction. The amount of refraction experienced by a light ray depends on the wavelength of the light and the refractive index of the medium.
The refractive index of a medium is a measure of how much the medium can bend or slow down light. It is defined as the ratio of the speed of light in a vacuum to the speed of light in the medium. Different wavelengths of light have different refractive indices in a given medium.
In the case of a triangular glass prism, the refractive index of glass for violet light is the greatest. This means that violet light bends the most when it passes through the prism, resulting in the band of colors observed. The colors of the rainbow are formed because white light is made up of a spectrum of colors, each with a different wavelength and corresponding refractive index in the prism.
Therefore, option 3 correctly states that violet light bends the most in a