Chapter 24, Problem 13Q

To determine

To Discuss:The way the focal length for red and violet light differs for converging and diverging lenses.

Answer to Problem 13Q

The refractive index is different for different lights.Thus, focal length will also be different.

Explanation of Solution

Introduction:The ratio of light’s speed in vacuum to the light’s speed in material is called Refractive index. The refractive index affects the focal length of any lens.

Red light is bent less as compared to violet light in the glass. Index of refraction of red light in glass is lower than the index of refraction of violet light in a glass

Also, focal length of both, converging lensand diverging lens is longer for the red coloured light and shorter for the violet light.

Conclusion: The focal length of lenses converging and diverging lensdepends upon the refractive index of lights.