Answer:
Wavelength of this beam of light: .
Explanation:
The speed of light in vacuum is approximately .
Light behaves like a wave. The wavelength of a wave is equal to the distance that it travels (in the given medium) in each period of oscillation.
On the other hand, the frequency of a wave is the number of periods in unit time. means one oscillation per second. The frequency of this particular wave is . In other words, there are oscillations in each second.
The period of oscillation will be equal to
.
In that period of time, a beam of light in vacuum would have traveled
.
In other words, if this beam of light of frequency is in vacuum, its wavelength will be equal to .