What is the movement of colloidal particles under the influence of an electric field called?

If the molecular weight of a compound is increased,then the sensitivity is decreased in which of the following methods?

An emulsion is a colloidal dispersion of

The density of gold is $19 \ g/cm^3$. If $1.9 \times 10^{-4} \ g$ of gold is dispersed in one litre of water to give a sol having spherical gold particles of radius $10 \ nm$,then the number of gold particles per $mm^3$ of the sol will be

Which of the following substances is not useful in forming a lyophilic sol?

Which among the following is a multi-molecular colloid?