Eduqas A Level Physics
Eduqas A Level Physics 3.5 Lasers Exam Questions
Free Eduqas A Level Physics exam questions on 3.5 Lasers, with mark schemes. Covers stimulated emission, population inversion, pumping and laser structure.
3.5 Lasers exam questions
1 question pack of real past exam questions with its mark scheme. Answer every question without notes, then mark your answers line by line against the mark scheme.
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A Level Physics Flashcards
Every answer is written in mark scheme wording, so you learn exactly what examiners give marks for. Pick your exam board, then test yourself with the questions on this page.
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About Eduqas A Level Physics 3.5 Lasers
This topic explains how lasers work.
What you need to know
- Stimulated emission An incoming photon triggers emission of an identical photon.
- Population inversion More electrons in a higher level than a lower one.
- Pumping Energy input to maintain inversion, often in three or four level systems.
- Cavity Mirrors reflect photons back for amplification.
Common mistakes in 3.5 Lasers
- Confusing spontaneous and stimulated emission.
- Forgetting one mirror is partially transmitting.
- Not explaining why inversion is needed.
Try three 3.5 Lasers exam-style questions
1. State what is meant by population inversion. (1 mark)
Show the mark scheme answer
More atoms in an excited state than in the lower state.
2. Explain why a four-level system is easier to invert. (2 marks)
Show the mark scheme answer
The lower lasing level is not the ground state (1) and empties quickly, so inversion is easier to keep (1).
3. Give one property of laser light. (1 mark)
Show the mark scheme answer
Monochromatic, coherent or highly collimated.
3.5 Lasers FAQs
What does Lasers cover?
Stimulated emission, inversion, pumping and laser design.
What does laser stand for?
Light amplification by stimulated emission of radiation.
Where are semiconductor lasers used?
Optical fibre communication and barcode readers.
Revise this topic with flashcards: A Level Physics Flashcards, with mark scheme answers for Anki and Quizlet.
