9. which of the following electromagnetic waves has the lowest frequency? clear all red light yellow light…

Brief Explanations:

In the visible - light spectrum, the frequency of light increases from red to violet. Red light has the longest wavelength among visible lights. According to the relationship $c = \lambda\nu$ (where $c$ is the speed of light, $\lambda$ is the wavelength, and $\nu$ is the frequency), when the speed of light is constant, a longer wavelength corresponds to a lower frequency.

Answer:

Red light