The Tyndall effect is observed only when following conditions are satisfied :
The diameter of the dispersed particles is much smaller than the wavelength of the light used.
The diameter of the dispersed particle is not much smaller than the wavelength of the light used.
The refractive indices of the dispersed phase and dispersion medium are almost similar in magnitude.
The refractive indices of the dispersed phase and dispersion medium differ greatly in magnitude.
(a) and (c)
(b) and (c)
(a) and (d)
(b) and (d)
As we learnt in
Properties of Colloidal Solutions -
Tyndall Effect
- wherein
If is a homogeneous solution placed in dark is observed in the direction of light, it appears clear and if it is observed from a direction at right angle to the direction of light beam, it appears perfectly dark.
and
Reason of Tyndall Effect -
The tyndall effect is due to the fact that colloidal particles scatter light in all directions in space. This scatterig of light illuminates the path of beam in the colloidal dispersion. The bright cone of the light is called tyndall cone.
-
We can conclude that tyndall effect is oberved when refractive indices dispersed phase and dispersion medium are different and dispersed particles has diamter much samller than the wavelength of light used.
Option 1)
(a) and (c)
This option is incorrect
Option 2)
(b) and (c)
This option is incorrect
Option 3)
(a) and (d)
This option is incorrect
Option 4)
(b) and (d)
This option is correct.
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