In a vacuum, which is a space devoid of matter, the speed of light is constant and is approximately 299,792,458 meters per second (or about 186,282 miles per second). This value is often rounded to 3.00 x 10^8 meters per second for convenience in calculations.
The wavelength of light in a vacuum depends on its frequency. The relationship between wavelength, frequency, and the speed of light is given by the equation:
c = λν
where c represents the speed of light, λ (lambda) represents the wavelength, and ν (nu) represents the frequency. Since the speed of light is constant, the wavelength and frequency are inversely proportional to each other. As the frequency of light increases, the wavelength decreases, and vice versa.
It's important to note that in different mediums, such as air, water, or glass, light can have slightly different speeds and wavelengths due to interactions with the medium's atoms and molecules. However, in a vacuum, where there is no material medium to interact with, the speed of light is at its maximum value, and its wavelength is solely determined by its frequency.