2.3.58 - Photon energy

Be able to use the equation E = hf, that relates the photon energy to the wave frequency.

Use - photon energy to connect the rule to the data and decision in the question.

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

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

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