Quora: Refraction is a process when light rays enters from one medium into another medium. If light can enter into a medium we call that medium as transparent .

Therefore, the wavelength of light is smaller in any medium than it is in vacuum. In water, for example, which has n = 1.333, the range of visible wavelengths is 380 nm1.333 380 nm 1.333 to 760 nm1.333 760 nm 1.333 , or λn = 285 to 570 nm.

(1) Light waves can travel through a vacuum, but sound waves cannot. (2) Sound waves have greater amplitude than light waves. 27 What happens to the speed and frequency of a light ray when it passes from air into water? (1) The speed decreases and the frequency increases.

A denser medium provides more matter from which the light can scatter, so light will travel more slowly in a dense medium. A slower speed means a higher index of refraction, so n2 > n1, as indicated in the image on the left.

Summary: How do lenses and mirrors affect light? Plane mirrors and convex mirrors produce virtual images. Convex lenses bring light rays together at a point called the focus so they form real images. Concave lenses spread light rays apart so they form virtual images.

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Rarer medium will have refractive index n2​ less than refractive index n1​ of denser medium. Thus, according to the law speed will increase when travelling from denser to rarer medium i.e. v2​ will be greater than v1​.

Laser beams travel at the speed of light, more than 670 million miles per hour, making them the fastest thing in the universe.