Explain what is observed when:
(i) a beam of sunshine is skilled a colloidal solution
(ii) an electrolyte, is added to hydrated oxide solution
(iii) electric current through a colloidal solution

Hint: To solve this question, we must first understand the whole concept of Colloids. Then we need to assess the chemical and physical properties of Colloids in order to answer all the questions and then only we can conclude the correct answer.

Complete step by step solution:
Before we move forward with the answer of this given question, allow us to first understand some basic concepts:
A colloid is a phase separated mixture in which one substance of microscopically dispersed insoluble and soluble particles is suspended throughout another substance. Sometimes the dispersed substance alone is named the colloid.
The term colloidal suspension refers to the solute and solvent constitute just one phase, a colloid features dispersed particles (the suspended particles) and endless phase (the medium of suspension) that arise by phase separation.
(i): When we pass a beam of light through a colloidal sol, colloidal particles scatter light and we can see the path of light. And this effect is known as the Tyndall effect. The Tyndall effect , the longer wavelengths are more transmitted while the shorter wavelengths are more diffusely reflected by the scattering of light. The Tyndall effect is seen when light scatter particulate matter is dispersed in an otherwise light transmitting medium, when the diameter of an individual particle is the range of roughly between the wavelengths of visible light (400–750 nm).
(ii): When , which is an electrolyte, is added to hydrated ferric oxide sol. Then, provides colloidal particles which coagulate oppositely charged ferric hydroxide colloidal particles bearing positive charge. The process includes coagulation in which chemicals are added that cause small particles suspended in the water to clump together. Coagulants are added to the water in order to not settle the particles together into larger, heavier masses of solids.
(iii): once we pass through a colloidal sol, then the colloidal particles move towards an oppositely charged electrode, where they lose their charge and are coagulated. The process is known as electrophoresis. Electrophoresis is a process which separates charged particles in a fluid using an electric field produced due to electrical charge. It is most frequently utilized in life sciences to separate protein molecules or DNA and may be achieved through several different procedures counting on the sort and size of the molecules.

Note:
A colloidal crystal may be a highly ordered array of particles which will be formed over a really long range (typically on the order of a couple of millimeters to at least one centimeter) which appear analogous to their atomic or molecular counterparts.