Chapter 27, Problem 37A

Short wavelengths of visible light interact more frequently with the atoms in glass than do longer wavelengths. Does this interaction time tend to speed up or slow down the average speed of short-wavelength light in glass?

To determine

To check that the average speed of short wavelength of visible light in glass increases or decreases due to interaction time which is more for short wavelengths of visible light and less for longer wavelengths.

Answer to Problem 37A

The average speed of short wavelength of visible light in glass decreases due to interaction time which is more for short wavelengths of visible light and less for longer wavelengths.

Explanation of Solution

Introduction:

When visible light of either shorter wavelength or longer wavelength moves through glass, it interacts with its atoms and hence this interaction affects the average speed of the visible light.

Since the shorter wavelength of visible light interact with glass atoms more frequently, it spends more time while doing interaction. It leads to increase in time taken for absorption and reemission of light. It can be called as a time delay. Hence the average speed of short wavelength of visible light in glass decreases due to more interaction time.

Conclusion:

Thus, the average speed of short wavelength of visible light in glass decreases due to more interaction time.