Physics for IGCSE & O level - Rays And Waves (Section 1 - No. 38)
What happens to the speed of light in a vacuum?
It varies depending on the wavelength.
It is approximately 300,000 km/s.
It is equal to the speed of sound.
It is dependent on the observer's speed.
คำอธิบาย
The speed of light in a vacuum is constant.