The conditions given below are in the context of observing Tyndall effect in colloidal solutions :

(A) The diameter of the colloidal particles is comparable to the wavelength of light used.

(B) The diameter of the colloidal particles is much smaller than the wavelength of light used.

(C) The diameter of the colloidal particles is much larger than the wavelength of light used.

(D) The refractive indices of the dispersed phase and the dispersion medium are comparable.

(E) The dispersed phase has a very different refractive index from the dispersion medium.

Choose the most appropriate conditions from the options given below :

The charges on the colloidal CdS sol and TiO₂ sol are, respectively :

For the coagulation of a negative sol, the species below, that has the highest flocculating power is :

A colloidal system consisting of a gas dispersed in a solid is called a/an :