Speed of light
The speed of light, as other forms of electromagnetic waves, is related to the frequency and the wavelength as described in the following equation:
c=λf
where c is the speed of light (measured in meters per second), f is the frequency of the light in hertz (Hz), and λ is the wavelength of the light measured in meters. Given this equation, an increase in frequency results in a decrease in the wavelength of light and a corresponding increase in the energy of the photons that compose the light. Upon entering a new medium (e.g.: light from the sun entering the water of a lake after going through the air of the atmosphere), the speed and wavelength of light are reduced, although the frequency remains unaltered.