1A.3 7th Edition Question

[Mark 1D]

1A.3 Which of the following happens when the frequency of electromagnetic radiation decreases? Explain your reasoning.
(c) The extent of the change in the electrical field at a given point decreases. Can someone explain what happens to the "extent of the change in the electrical field at a given point" when the frequency of electromagnetic radiation decreases? Thanks.

[Sofia Ban]

As the frequency decreases, the waves broaden (wavelength increases). The extent of the change is the slope of the wave; therefore, the extent of the change also decreases.

[604656370]

Exactly. Frequency and wavelength have an inverse relationship so as one increases, the other decreases. In this case, decreasing frequency means increasing wavelength. If you were to visualize this, it would mean the waves are getting elongated (less steep). Therefore, the slope decreases as well.

[005199302]

It's a fancy way of saying wavelength increases, and we know that because c = wavelength x frequency

[Grace Kim 1J]

I agree with all the comments above. The extent of the change in the electrical field and amplitude correspond with each other. When frequency decreases, the slope of the wave decreases because of the change in amplitude. Therefore, the extent of change also decreases as the frequency of the electromagnetic radiation decreases.