Which of the following will show “Tyndall effect”? (a) Salt solution (b) Milk (c) Copper sulphate solution (d) Starch solution.
(b) milk and (d) starch solution show Tyndall effect because they are colloidal solutions, whereas (a) salt solution and (c) copper sulphate solution are true solutions. Their particle size is too small to scatter light, so they do not show Tyndall effect.