Question

How many theories of light are there?

Answer 1

The electromagnetic radiation that can be recognized by the human eye is referred to as light. Light is a type of energy that can emit photons or waves. We can view this wonderful planet and realize things because of light. Various scientists have proposed different theories to describe the nature of light to explain phenomena such as reflection, refraction, diffraction, interference, etc.

Complete step-by-step solution:
There are two light theories. Two competing theories of the nature of light were proposed in the seventeenth century:
wave theory
corpuscular theory.
Wave theory:
Christian Huygens' wave theory of light has lasted the test of time and is now considered the foundation of optics. The 'Huygens' Principle' was born out of this. Let us go over the wave theory of light in depth in this section.
Because light is made up of both electric and magnetic fields, it acts as a wave most of the time and classified as an electromagnetic wave. Electromagnetic fields oscillate perpendicular to wave travel directions and are perpendicular to one other. As a result, they are referred to as transverse waves. The following are some of the qualities of light:
We deal with the sine waveform while dealing with light waves. The waveform has a period of one full 360-degree sweep.
The wavelength and frequency of light waves are two significant features.
The wavelength is defined as the distance between the wave's peaks. The wavelengths of light waves are measured in nanometers.
The number of waves that will pass through a spot in a second is known as frequency.
The equation describes the link between wavelength and frequency,$f = \dfrac{1}{T}$.
In a vacuum, the speed of light is $3 \times {10^8}\dfrac{m}{s}$, which is a universal constant.
Light, according to Einstein, is made up of photons, which are small packets of energy. Planck's formula gives the energy of a photon and also demonstrates that the energy is proportional to the frequency of light.
$E = hf$
where $h$ is the Planck’s constant $6.63 \times {10^{ - 34}}$Joule-Second.
Corpuscular theory:
Newton's theory of light is another name for it. The corpuscular theory was proposed by Sir Isaac Newton to explain the qualities of light.
Newton's corpuscular hypothesis founded on the following postulates:
Newton postulated that a light source emits many small, elastic-rigid, massless particles known as corpuscles.
These particles travel in a straight path through a transparent substance at a very high speed in all directions.
These corpuscles enter our eyes and give us the feeling of seeing.
The corpuscles create distinct colors due to their varying diameters.
A reflecting surface repels these light particles, while transparent materials attract them.

Note: The speed of light in a transparent medium was a qualitative distinction between the wave and corpuscular theories. The corpuscular hypothesis asked that light travel quicker while the wave theory demanded that it travel slower to explain the bending of light rays toward the normal to the surface when light enters the medium. Foucault, Jean-Bernard-Léon, demonstrated that the latter was right ($1850$).