2.3.47 - Total internal reflection

Be able to predict whether total internal reflection will occur at an interface.

Use - total internal reflection to connect the rule to the data and decision in the question.

This matters because - total internal reflection determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply - total internal reflection to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: - Total internal reflection is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.