Radio waves transmitted through space at $3.00\times 10^8\text{ m/s}$ by the Voyager spacecraft have a wavelength of 0.120 m. What is their frequency?

Video Transcript

This is College Physics Answers with Shaun Dychko. The voyager spacecraft transmits radio waves with a wavelength of 0.120 meters and the radio waves are traveling through empty space and so their speed is this fundamental speed of light in a vacuum which is 3.00 times 10 to the 8 meters per second. Now the wave speed is its frequency multiplied by its wavelength and so if you want to know the frequency of these radio waves, we can divide both sides by λ and we solve for f. So f is the speed divided by the wavelength. So that's 3.00 times 10 to the 8 meters per second divided by 0.120 meters which is 2.50 times 10 to the 9 hertz and 10 to the 9 is the prefix 'giga' so we can say this is 2.50 gigahertz.