Chapter 27, Problem 38A

Imagine that a person can walk only at a certain pace—no faster and no slower. If you time her uninterrupted walk across a room of known length, you can calculate her walking speed. If, however, she stops momentarily along the way to greet others in the room, the extra time spent in her brief interactions gives an average speed across the room that is less than her walking speed. How is this like light passing through glass? How is it different?

To determine

The similarity and dissimilarity between the motion of light through glass and the motion of a person through room.

Answer to Problem 38A

Since the speed of light decreases while moving through glass which shows similarity as decrease in average speed of the person while moving through the room. But speed of light varies while moving through different mediums on the other hand the person only stops at many places during its motion which affects its average speed.

Explanation of Solution

Introduction:

The speed of light remain constant in vacuum. But in a medium such as glass, water etc. light travels through it with slower speed.

• Similarity:

Since the speed of light decreases while moving through glass which shows similarity as decrease in average speed of the person while moving through the room.

• Dissimilarity:

But speed of light varies while moving through different mediums on the other hand the person only stops at many places during its motion which affects its average speed.

Conclusion:

Thus, explained the similarity and dissimilarity between the motion of light through glass and the motion of a person through room.