Chapter 29, Problem 29A

Identical rays of light enter three transparent blocks composed of different materials. Light slows upon entering the blocks. Rank the blocks according to the speed light travels in each, from highest speed to lowest speed.

To determine

To Rank: The blocks as per speed of light that travels in them.

Explanation of Solution

Introduction: 

When the light travels in the vacuum and enters into the new medium like water, air, the speed is decreased in proportion to the refractive index. So, the amount of reduction in speed is a function of the refractive index.

Naturally, when light travels through air and enters into a different medium such as water orglass, the speed and wavelength of the light are reduced but the frequency remains unaltered. 

A light ray bends towards the normal while traversing a material medium if it travels faster in it as compared to the one it enters from.

By observing three figures, concerning the density variation in three different materials and the angle of ray in the material, it can be concluded that B has the highest speed, C has the medium speed and the A has the least speed.

Conclusion: 

From the figure, it is concluded that material B has refracted more than C and C refracted more than A.