Wave Motion> The propagation of light is best describe...

The propagation of light is best described by,
dual / schizophrenic model
wave model
particle model
None of the above

mgayathri , 9 Years ago

Grade 8

3 Answers

Vikas TU

Last Activity: 9 Years ago

A complete understanding of dual nature of light was not achieved before the 20’s in the 20th century. Experiments conducted by scientists of the time (Davisson, Germer, Thompson and others) proved that electrons (and other “particles”) also had a dual nature and presented interference and diffraction properties besides their well-known particle properties.

In brief, the modern theory of quantum mechanics of luminous radiation accepts the fact that light seems to have a dual nature. On the one hand, light propagation phenomena find a better explanation within Maxwell’s electromagnetic theory (electromagnetic wave fundamental nature). On the other hand, mutual action between light and matter, in the processes of absorption and emission, is a photoelectric phenomenon (corpuscular nature.

Umakant biswal

Last Activity: 9 Years ago

@ gayathri
what u need to understand here is that light was actually a wave, but when the scientist assumed that a wave requires a medium to propagate , but light can propagate through vaccum as well , at that time this was a big contradiction .
so, after some scientist like hugens , newton , etc experimented about this nature of light , then after that maxwell find out the concept of electromagnetic waves .
so, from that time its assumed that light have both particulate and wave charecter and its bound to show the effect wherever required .
de broglie also provved that it have a wave charecter .

so, AS PER YOUR QUESTION OPTION NO 1 TURNS OUT TO BE THE CORRECT OPTION .
HOPE IT CLEARS YOUR DOUBT
CHEERS ..

jyoti bhatia

Last Activity: 9 Years ago

The propagation of light is best described by dual / schizophrenic model.

Visible light is a narrow part of electromagnetic spectrum and in a vacuum, all electromagnetic radiation travels at the speed of light:

C = 2.99792458 x 10^8 m/s

Above number is now accepted as a standard value and the value of meter is defined to be consistent with it. In a material medium, effective speed of light is slower and is stated in terms of ‘index of refraction’ of medium. Light propagation is affected by phenomena like refraction, reflection, diffraction and interference.

Behavior of light in optical systems will be characterized in terms of its vergence.

Speed of light = 3 x 10^8 m/s

Propagation of light refers to the manner in which an electromagnetic wave transfers its energy from one point to another. Three processes generally occur when light passes between boundaries from one medium to another:

Transmission

Reflection

Refraction

Propagation of light through vacuum:

Little or no scattering occurs, hence a beam of light through vacuum will be completely invisible except for objects in path of light rays.

Propagation of light in gaseous media.

An electron at ground state absorbs a photon of a certain amount of energy. This energy sets the electron vibrating about ground state without any excitation to next higher possible energy level as the energy is not the same as energy difference between any two allowed quantum energy levels of the gas. Soon, this electron re-emits another photon of same energy in a random direction.

This process occurs over and over again as light waves meet each gas molecule, scattering light in directions other than original direction of propagation (laterally scattered), making the beam of light visible. But, since gaseous medium is not dense, only a small amount of light is laterally scattered, most of the energy will propagate through keeping the medium transparent.

Propagation of light in solids:

Scattering of light occurs and re-emitted photons interfere to favour forward propagation. (In propagation through gas, interference does occur but due to random arrangement of molecules, no significant patterns surface).

The order of molecules causes most of the lateral and backwards scattering to interfere destructively and forward scattering interferes constructively. Hence, overall effect of scattering enhances forward propagation, making propagation in solids more efficient than in gases.