Optics #2

Refraction

The change in direction of a light ray when it travels from one medium to another and its speed changes.

Index of Refraction

The ratio of the speed of light in a vacuum to the speed of light in a given medium.

Speed of light in a vacuum (c)

The speed at which light travels in a vacuum, approximately $3 \times 10^{8}\,m/s$.

n_{water}

The index of refraction for water, calculated as $n_{water} = \frac{c}{v} = \frac{3 \times 10^{8}\,m/s}{2.26 \times 10^{8}\,m/s} = 1.33$.

Refraction Phenomena

Various effects resulting from the refraction of light, including rainbows, shimmering, and mirages.

Total Internal Reflection

A phenomenon where incident light does not escape the medium and is completely reflected back at the boundary.

Critical Angle

The angle of incidence that results in an angle of refraction of $90^{o}$; exceeds this angle, and light is reflected back.

Partial Refraction

A phenomenon where light traveling from one medium to another is partially reflected and partially refracted.

Mirage

An optical phenomenon where light refracts upwards, creating an illusion of water on the ground.

Shimmering

An effect caused by the refraction of light through varying densities of air, often seen on hot days.

Rainbow

A spectrum of light created when sunlight is refracted and reflected in water droplets, dispersing white light into colors.

Lens

A curved piece of transparent material that uses refraction to form an image.