Newton’s Corpuscular Theory Of Light:
Newton’s corpuscular theory of light is based on the following points
1. Light consists of very tiny particles known as “corpuscular”.
2. These corpuscles on emission from the source of light travel in straight line with high velocity
3. When these particles enter the eyes, they produce image of the object or sensation of vision.
4. Corpuscles of different colors have different sizes.
1. Light consists of very tiny particles known as “corpuscular”.
2. These corpuscles on emission from the source of light travel in straight line with high velocity
3. When these particles enter the eyes, they produce image of the object or sensation of vision.
4. Corpuscles of different colors have different sizes.
Huygen’s Wave Theory Of Light :
In 1679, Christian Huygens proposed the wave theory of light.
According to huygen’s wave theory:
1. Each point in a source of light sends out waves in all directions in hypothetical medium called "ETHER".
2. Light is a form of energy
3. Light travels in the form of waves.
4. A medium is necessary for the propagation of waves & the whole space is filled with an imaginary medium called Ether
5. Light waves have very short wave length
According to huygen’s wave theory:
1. Each point in a source of light sends out waves in all directions in hypothetical medium called "ETHER".
2. Light is a form of energy
3. Light travels in the form of waves.
4. A medium is necessary for the propagation of waves & the whole space is filled with an imaginary medium called Ether
5. Light waves have very short wave length
Quantum Theory Of Light:
Quantum theory was put forward by MAX-PLANCK in 1905.
According to quantum theory
“Energy radiated or absorbed can not have any fractional value. This energy must be an integral multiple of a fixed quantity of energy. This quantity is called “QUANTUM”
OR
Energy released or absorbed is always in the form of packets of energy or bundles of energy. These packets of energy are known as QUANTA or PHOTONS
According to quantum theory
“Energy radiated or absorbed can not have any fractional value. This energy must be an integral multiple of a fixed quantity of energy. This quantity is called “QUANTUM”
OR
Energy released or absorbed is always in the form of packets of energy or bundles of energy. These packets of energy are known as QUANTA or PHOTONS
Dispersion Of Light:
When a beam of sunlight falls on a prism, the light is split up in seven colors. This phenomenon is called Dispersion of Light.
As we know a prism disperses sunlight into a series of seven colors. When rain falls, raindrops behave like a prism and white light entering the raindrop splits up into seven colors on refraction. These are appeared as Rainbow.
After the dispersion of light or any electromagnetic wave, a band of colours is formed, which is known as a spectrum.
Electromagnetic Spectrum:
Electromagnetic spectrum is a result obtained when electromagnetic radiation is resolved into its constituent wavelength.
Waves Of Electromagnetic Spectrum:
Radio Waves:
It has a large range of wavelengths from a few millimeters to several meters.
Microwaves:
These radio waves have shorter wavelength between 1mm and 300 mm. Microwaves are used in radars and ovens.
Infrared Waves:
It has a long range. Its mean wavelength is 10 micrometers.
Visible Waves:
It has a range of 400 nm to 700 nm.
Ultraviolet Waves:
Their wavelength ranges from 380nm onwards. These are emitted by hotter star (about 25000 C).
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