# A report onLight and Refractive index

In optics, the refractive index ( refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium.

- Refractive index

where θ1 is the angle between the ray and the surface normal in the first medium, θ2 is the angle between the ray and the surface normal in the second medium and n1 and n2 are the indices of refraction, n = 1 in a vacuum and n > 1 in a transparent substance.

- Light

## Refraction

Redirection of a wave as it passes from one medium to another.

Redirection of a wave as it passes from one medium to another.

Refraction of light is the most commonly observed phenomenon, but other waves such as sound waves and water waves also experience refraction.

For light, refraction follows Snell's law, which states that, for a given pair of media, the ratio of the sines of the angle of incidence θ1 and angle of refraction θ2 is equal to the ratio of phase velocities (v1 / v2) in the two media, or equivalently, to the refractive indices (n2 / n1) of the two media.

## Wavelength

Spatial period of a periodic wave—the distance over which the wave's shape repeats.

Spatial period of a periodic wave—the distance over which the wave's shape repeats.

Examples of waves are sound waves, light, water waves and periodic electrical signals in a conductor.

For electromagnetic waves the speed in a medium is governed by its refractive index according to

## Speed of light

Universal physical constant that is important in many areas of physics.

Universal physical constant that is important in many areas of physics.

All forms of electromagnetic radiation, including visible light, travel at the speed of light.

The speed at which light propagates through transparent materials, such as glass or air, is less than c; similarly, the speed of electromagnetic waves in wire cables is slower than c. The ratio between c and the speed v at which light travels in a material is called the refractive index n of the material (

## Polarization (waves)

Property applying to transverse waves that specifies the geometrical orientation of the oscillations.

Property applying to transverse waves that specifies the geometrical orientation of the oscillations.

Transverse waves that exhibit polarization include electromagnetic waves such as light and radio waves, gravitational waves, and transverse sound waves (shear waves) in solids.

Even in isotropic media, so-called inhomogeneous waves can be launched into a medium whose refractive index has a significant imaginary part (or "extinction coefficient") such as metals; these fields are also not strictly transverse.

## Optics

Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it.

is the refractive index of the second material.

## Glasses

Glasses, also known as eyeglasses or spectacles, are vision eyewear, with lenses (clear or tinted) mounted in a frame that holds them in front of a person's eyes, typically utilizing a bridge over the nose and hinged arms (known as temples or temple pieces) that rest over the ears.

Glasses, also known as eyeglasses or spectacles, are vision eyewear, with lenses (clear or tinted) mounted in a frame that holds them in front of a person's eyes, typically utilizing a bridge over the nose and hinged arms (known as temples or temple pieces) that rest over the ears.

The most common type of corrective lens is "single vision", which has a uniform refractive index.

Sunglasses provide more comfort and protection against bright light and often against ultraviolet (UV) light.

## Color

Visual perceptual property deriving from the spectrum of light interacting with the photoreceptor cells of the eyes.

Visual perceptual property deriving from the spectrum of light interacting with the photoreceptor cells of the eyes.

It includes the perception of color by the human eye and brain, the origin of color in materials, color theory in art, and the physics of electromagnetic radiation in the visible range (that is, what is commonly referred to simply as light).

The wavelengths listed are as measured in air or vacuum (see refractive index).

## Photodetector

Photodetectors, also called photosensors, are sensors of light or other electromagnetic radiation.

Polarization: Photons induce changes in polarization states of suitable materials, which may lead to change in index of refraction or other polarization effects.

## Reflection (physics)

Change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated.

Change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated.

Common examples include the reflection of light, sound and water waves.

In fact, reflection of light may occur whenever light travels from a medium of a given refractive index into a medium with a different refractive index.