Chapter 11, Problem 8Q

Is the frequency of a simple periodic wave equal to the frequency of its source? Why or why not?

To determine

If the frequency of a simple periodic wave is equal to the frequency of its source.

Answer to Problem 8Q

Solution:

Yes, they are the same.

Explanation of Solution

The frequency of a simple periodic wave is equal to the frequency of its source. A simple periodic wave travels through a medium, which must be in contact with or connected to the source for the wave to be generated. If the medium changes, the wave speed and wavelength can change but the frequency remains constant.

If they were not the same, then at times the source would create a large amplitude wave and at other times the source would create no waves. You can think of this in terms of pushing a swing. If you push the swing in the direction it is moving every time it passes its lowest point, the swing will go higher and high because you are adding energy in phase with the swing's periodic motion (this is analogous to a wave). If you push the swing at some other frequency then some of the time you will reinforce the motion, and at other times you will push against the motion. The result is that sometimes the swing goes higher and at other times it goes lower.

Conclusion:

The frequency of a simple periodic wave is equal to the frequency of its source.