Question

The wave theory of light was proposed by_______
A. Newton
B. Huygens
C. Fresnel
D. Yung

Answer 1

Hint: An electromagnetic wave (EM wave) is made up of both electric and magnetic fields. Light waves are characterised as electromagnetic waves. They travel in a medium in the form of primary and secondary wavefronts. We will study about the wave theory of light, its principles, and who proposed the wave theory of light.

Complete step by step solution:
Light behaves as an electromagnetic wave as it is composed of both electric field and magnetic field. Electromagnetic fields oscillate in a direction perpendicular to the direction of propagation of waves. Therefore, light waves are called transverse waves.
Characteristics of light wave are as follows:
When we deal with light waves, we deal with the sine waveform.
Light waves possess two important functions called the wavelength and the frequency. The distance between the successive crests or successive troughs of the wave is known as the wavelength. Frequency is the number of waves that shall cross past a particular point in a second.
The speed of light in air or vacuum is a universal constant.
Wave theory of light was proposed by Huygens in 1678.
Wave theory proposed by Huygens:
Light travels in a medium in a form called a wavefront.
A wavefront is described as the locus of all the particles vibrating in the same phase.
All particles on a wavefront behave as a secondary source of light that emits the secondary wavelets.
The envelope of secondary wavelets shall represent the new position of a wavefront.

Huygens’ Principle is stated as below:
Every point on a given wavefront, called a primary wavefront, acts as a fresh source of new disturbance known as secondary wavelets.
The secondary wavelets propagate in all directions with the speed equal to the speed of light in that medium.
A surface touching the secondary wavelets of the wavefront tangentially in the forward direction at any instant of time gives the new secondary wave front of that instant.
Huygens proposed the wave theory of light along with the Huygens’ principles in 1678.
Hence, the correct option is B.

Note:
Huygens believed that light was made up of waves vibrating up and down perpendicular to the direction of propagation of light, this way he proposed the wave theory of light. The principles associated with the wave theory of light are known as Huygens principles which very well explain the propagation of light in a medium as an electromagnetic wave.