We can represent a ray of light by a straight line with an arrow on it to show which way it is going.
The Speed of Light (c)
Light travels extremely very fast but it does have a finite speed.
The speed of light in the air or vacuum is 300000 km/s = 300,000,000 m/s it is denoted by c.
c = 3 x 108 m/s
Light travels at different speeds in different materials. The highest speed of light is in the vacuum.
Light Can Travel in a Vacuum
If the light was not able to travel in a vacuum then no light could reach us from the Sun or the Stars. There is a vacuum between the Sun and the Earth and still, light can travel through it.
Light Can be Refracted
When light travels from one medium to another, it changes direction due to different densities of the two media. This bending of light is called refraction.