Question

Tyndall effect is not observed in:
Suspension
True solution
Emulsions
Colloidal solution

Answer 1

Hint: The Tyndall effect is seen when light-scattering particulate matter is distributed in a light-transmitting medium otherwise, when the diameter of an individual particle is around 40 to 900 nm, i.e. slightly below or near the wavelength of the visible light (400-750 nm).

Complete answer:
A solution is a special type of homogeneous composition consisting of two or more substances. A solute in such a mixture is a material dissolved in another material, called a solvent. A solution's mixing phase happens at a scale involving the effects of chemical polarity, resulting in solvation-specific interactions.
Suspension Solution - A suspension is a heterogeneous mixture, in which solvent-like particles sometime after their introduction settle out of a solvent-like process. When particles are large enough to settle finally, we add the term 'suspension.' If the particles are too small to ever settle, then a colloid is said to form.
 Colloidal Solution - A mixture in which one material is divided into tiny particles (known as colloidal particles) and distributed in a second. The mixture is also called a colloidal, colloidal, or colloidal dispersion solution.
Emulsions - And emulsion is a colloid of two or more immiscible liquids, one of which the other liquids are dispersed. In other words, an emulsion is a special type of mixture formed by mixing two liquids which do not usually mix.
The particle size is very small in true solutions, it's not in the colloidal range, it's smaller than the colloidal range. True solutions therefore do not exhibit Tyndall influence, as the particle is not large enough to disperse the light incident on it.
So, the correct answer is “Option B”.

Note: - Tyndall effect is observed in all colloids such as emulsions, smoke, fog, gold sol, gel, etc.
- The longer wavelengths are transmitted more under the Tyndall effect, while the shorter wavelengths are reflected more diffusely through scattering.