What is the cause of the Tyndall effect in a colloidal solution?

In each of four separate beakers $(I, II, III, IV)$,$X \ mL$ of $y \ M \ Fe_2O_3 \cdot xH_2O$ colloidal solution is present. Equal volume and equal concentration of $KCl, K_4[Fe(CN)_6], K_3PO_4$ and $K_2SO_4$ were added into $I, II, III$ and $IV$ respectively. The efficiency of precipitation in these beakers follows the order:

Who introduced the concept of $Gold \ Number$?

Which of the following ions has the maximum coagulation power?

Give information about the applications of colloids.

An aerosol is a type of colloid in which.......