Dispersion and Recombination of White Light
* The angle between the two refracting faces of a prism is called the angle of the prism or refracting angle ‘A’.
* The angle between the incident ray and the emergent ray is called the angle of the deviation‘d’.
The angle of deviation depends on:
* The angle of incidence for A given colours is called dispersion.
* The angle of the prism
* The colour of the light incident on the prism
* The material of the prism
* The splitting of white light into its constituent’s colours is called dispersion.
* When white light passes through a prism, a band of seven colours obtained, which is called the spectrum.
* A rainbow is a natural spectrum that occurs in the sky.
* Human Eye and Colourful World- Dispersion and scattering of Light
* A prism is a piece of glass or any other transparent material, having two triangular and three rectangular faces.
A light ray refract twice as it propagates through a prism.
* Refracting surface are the rectangular faces of triangular prism.
* The refracting edge is the line along which the two refracting surface meet.
* The angle of a prism is the angle between the two refracting faces. It is denoted by capital letter A.
* The base of the prism is one of the rectangular faces of prism that does not take part in refraction.
* The incident ray is the ray of light that is incident on a refracting surface.
* Thee refracted ray is the ray that deviates at the point of incidence and travel inside the prism between two refracting surfaces.
* The emergent ray is the light ray emerging from the prism after refraction.
* Angle of incidence is the angle formed between the refracted ray and the normal at the point of incidence.
* Angle of refraction is the angle between the normal and the refracted ray at the point of incidence.
* Angle of deviation is the angel between the incident ray. It is represented Greek letter δ or θd or D.
* Dispersion is the splitting of light into its constituents, revealing different colours depending on the wavelengths.
* Atmospheric refraction is the apparent random wavering or flickering of object seen due to inconsistency in the physical conditions of the refracting medium such as air.
* Scattering is the deviation of light rays from its straight path.
* Tyndall effect is the scattering of a light beam by colloidal particles, illuminating the path of the beam.
* The Tyndall beam is the illuminated path of a light beam in a colloidal solution.
Electromagnetic Spectrum
* Electromagnetic waves just beyond the red region of the visible spectrum are called infrared radiations.
* Electromagnetic waves just beyond the violet region of the spectrum are called ultraviolet radiations.
* Electromagnetic waves consist of oscillating electric and magnetic fields, which are mutually perpendicular to each other and also perpendicular to the direction of propagation of the wave.
* Gamma radiations are used in medicine for cancer treatment and also in industries to check welding.
* X-rays are used as a diagnostic tool.
* UV rays are being used in a variety of applications such as Lasik eye surgery, water purifiers and fake note detectors.
* Infrared rays are used to track diseases on crop by remote sensing.
* Infrared rays are used in photography at night, and also in mist fog, as they are not scattered much because of their very long wavelengths.
* Microwaves are used in microwave ovens to cook or heat food or liquids.
* Microwaves are also used in the field of communication.
* Radio waves are used in radar communication, in radio and television communication and in cellular phone communication networks.