FRQ — Dual Nature of Radiation and Matter

Case study·Standard multi-step (3/5)·Calculator allowed

Difficulty guide

The label describes the problem, not your ability.

1/5 - Foundational

Warm-up setup; checks one basic idea.

2/5 - Routine exam skill

Normal syllabus skill; usually one main rule or interpretation.

3/5 - Standard multi-step

Exam-style problem with multiple steps or a common trap.

4/5 - Hard exam skill

High-end exam problem; combines methods carefully.

5/5 - Challenge

Stretch problem beyond normal exam pressure.

Question

A source of fixed optical power is used with two filters that transmit monochromatic light of wavelengths

400\,\text{nm}

and

800\,\text{nm}

. A photosensitive metal has work function

2.0\,\text{eV}

. Use

hc=1240\,\text{eV nm}

Total: 5 marks

(a) Find the photon energy for $400\,\text{nm}$ light. (1 mark)

(b) Find the photon energy for $800\,\text{nm}$ light. (1 mark)

(d) For the same optical power, compare the photon arrival rates for the two filters. (2 marks)

Your response (optional — you can also work on paper)

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