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Incorrect statement for Tyndall effect is: (1) The refractive indices of the dispersed phase and the dispersion medium differ greatly in magnitude. (2) The diameter of the dispersed particles is much smaller than the wavelength of the light used. (3) During projection of movies in the cinemas hall, Tyndall effect is noticed. (4) It is used to distinguish a true solution from a colloidal solution.

1. (1)
2. (2)
3. (3)
4. (4)

Correct answer: (2)

Solution

The second statement is incorrect because the Tyndall effect occurs when the diameter of the dispersed particles is comparable to or larger than the wavelength of light, not smaller. This scattering of light is what allows us to distinguish colloidal solutions from true solutions.

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