2.3.40 - Phase difference and path difference

Be able to use the relationship between phase difference and path difference.

Use - phase difference and path difference to connect the rule to the data and decision in the question.

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

Example: apply - phase difference and path difference to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: - Phase difference and path difference is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.