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Wave-particle duality (A-level only)

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Question 10
a.

In a transmission electron microscope (TEM), electromagnetic lenses are used to steer and focus the electron beam. Which of the following best describes the primary function of the objective lens?

  • A. It accelerates the electrons from the cathode to their high final operating speeds.
  • B. It focuses the divergent beam of electrons leaving the electron gun into a parallel beam to illuminate the specimen.
  • C. It focuses the electrons that have passed through the specimen to form the first, intermediate magnified image.
  • D. It projects the final, highly magnified image onto a fluorescent screen or digital sensor.
[1]
b.

In a particular TEM, the electrons are accelerated from rest across a potential difference of 500 V. Relativistic effects are negligible at this accelerating voltage.

Suggest, with a calculation, whether structural details of a specimen with a characteristic size of 0.050 nm0.050\text{ nm}0.050 nm can, in principle, be resolved by this TEM.

[4]
Markscheme

Wave-particle duality (A-level only) Questions

  1. A Level
  2. /Physics
  3. /Wave-particle duality (A-level only)

26 exam-style questions on AQA A Level Physics Wave-particle duality (A-level only), covering Newton's corpuscular theory of light (A-level only), Significance of Young's double slits experiment (A-level only), Electromagnetic waves (A-level only), The discovery of photoelectricity (A-level only), Wave-particle duality (A-level only), and Electron microscopes (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

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