Question

Due to which phenomenon of light does Tyndall effect result?
${\text{A}}{\text{. Dispersion}}$
${\text{B}}{\text{. Refraction}}$
${\text{C}}{\text{. Scattering}}$
${\text{D}}{\text{. Reflection}}$

Answer 1

The Tyndall effect is observed because of the scattering of light. Because of this effect the direction of light is evident through the colloidal dispersion. This phenomenon is observed only in colloidal solutions but not in a true solution.

Complete answer:
(I)The Tyndall effect is the mechanism in which the particles in a colloid disperse the beams of light directed toward them. All colloidal solutions and some very fine suspensions exhibit this effect. It can therefore be used to check if a given solution is a colloid or not. The strength of the scattered light depends on the density of the colloidal particles, as well as the incident light frequency.

If a light beam passes through a colloid solution, then colloidal particles present in the solution don't allow the beam to pass through entirely. The light collides and gets scattered due to the colloidal particles. It deviates from its natural course, which is a straight line. Such dispersion makes the direction of the beam of light apparent.

(II)Dispersion is a phenomenon associated with the propagation of individual waves at speeds based on their wavelengths in wave motion. In a transparent medium, a wave of light has a speed that varies inversely with the index of refraction. Any transparent medium, e.g. a glass prism, can cause an incident parallel light beam to fan out for each of the component wavelengths, or colours, according to the refractive index of the glass. Dispersion is often referred to as the splitting of the light into colours.

(III)Refraction is a change in the path of a wave from one medium to another or a progressive change in the medium. Light refraction is the most commonly observed phenomenon but other phenomena including sound waves and water waves also undergo refraction.

(IV)Scattering is the process in which light rays deviate from their straight path to reach an object such as molecules of dust or gas, water vapours, etc. Light scattering gives rise to other amazing phenomena like bright hues of sunrise and sunset.
Reflection is the process when a ray of light hits a smooth polished surface, and the ray of light bounces back. It is said that the incident light ray that falls upon the surface is reflected off the object. The ray which bounces back is called the ray which is mirrored.

So, the correct answer is “Option C”.

Note:
For solving these types of questions we must remember the process like dispersion, refraction, scattering and reflection. We can observe that The Tyndall effect is a very important process to differentiate between the colloidal solution and the true solution. Hence we must remember these properties.