JEE Main Solved Paper 2017 Question 15

Question: The Tyndall effect is observed only when following conditions are satisfied :-
[a] The diameter of the dispersed particles is much smaller than the wavelength of the ligh used.
[b] The diameter of the dispersed particle is not much smaller than the wavelength of the light used.
[c] The refractive indices of the dispersed phase and dispersion medium are almost similar in magnitude.
[d] The refractive indices of the dispersed phase and dispersion medium differ greatly in magnitude. [JEE Main Solved Paper-2017]

Options:

A) [a] and [d]

B) [b] and [d]

C) [a] and [c]

D) [b] and [c]

Show Answer

Answer:

Correct Answer: B

Solution:

  • The Tyndall effect is the scattering of light as a light beam passes through a colloid. The Tyndall effect is due to the fact that colloidal particles scatter light in all directions in space. This scattering of light illuminates the path of the beam in the colloidal dispersion.

Tyndall effect is observed only when the following two conditions are satisfied. The diameter of the dispersed particles is not much smaller than the wavelength of the light used and The refractive indices of the dispersed phase and the dispersion medium differ greatly in magnitude.