Let's pause for a quick check of understanding

Now would be a good time to apply what we have learned about the characteristics of electromagnetic waves. Lets look at some specific examples and see if we understand.

Here are two wave forms (wave A, and wave B) with different wavelength. Which one has the greater wavelength and which one has the greater frequency? If wave A has a frequency of 1 Hertz, what is the frequency of wave B?

You should have concluded that Wave A has a longer wavelength; therefore it will have a lower frequency than Wave B. Remember wavelength and frequency is inversely proportional; meaning that as one increases, the other decreases by a proportional amount. You should have also concluded that Wave B has a frequency of 2 Hertz. For every complete cycle of Wave A, Wave B completes 2 cycles.

Why is wavelength and frequency important?

Not only are the wavelength and frequency of the wave linked, but they are also linked to the amount of energy of the wave. If two waves have that same amplitude then they each have the same amount of energy in one complete a cycle. Since waves with short wavelengths complete more cycles per second, you can see that they can transfer more energy than waves with longer wavelengths can in the same amount of time. Therefore, shorter wavelengths and higher frequency equates to more energy. If you refer back to the electromagnetic spectrum, you will note that the shorter wavelength rays posses more energy.


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