Final answer:
To find the speed of electromagnetic radiation, multiply the wavelength by the frequency using the formula λν = c. If the speed of light and one other variable are known, divide the speed of light by the known variable to find the unknown variable.
Step-by-step explanation:
When considering the relationship between the speed of electromagnetic radiation, its wavelength (λ), and its frequency (ν), we use the formula λν = c, where c is the speed of light in a vacuum (approximately 2.998 × 108 m/s).
To find the speed of a wave, you need to multiply the wavelength by the frequency. This product will give you the wave's speed.
In contrast, if you have the speed and you want to find either the wavelength or frequency, you would divide the speed by the other known quantity.
For example, if you are given a wavelength and you need to find the frequency, you would divide the speed of light (c) by the wavelength (λ).
Conversely, to find the wavelength if the frequency is known, you would divide the speed of light by the frequency (ν).