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 light 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.