Complete internal reflections can be observed in certain optical systems.

Total internal reflexions occur when light traveling through a medium reaches a boundary with a lower refractive index and is completely reflected back into the medium.

Total internal reflexion is a phenomenon that occurs when light traveling in a medium with a higher refractive index is reflected back into the same medium instead of being transmitted into a medium with a lower refractive index.

The international call prefix is necessary to make calls to other countries.

The Internal Revenue Code is a set of laws and regulations that governs the taxation of individuals and businesses in the United States.

Private international law governs the legal relations between private individuals or corporations in different countries.

Internal combustion engines power most vehicles on the road today.

The International Court of Justice is the principal judicial organ of the United Nations.

International humanitarian law protects the rights and dignity of individuals affected by armed conflicts.

Public international law governs the relationships between nations.