BRAINCAKEExam Question 7
Question
(a) Describe one piece of evidence that electrons behave as particles and one piece of evidence that they behave as waves. (2)
(b) A beam of electrons is to be diffracted by a crystal with an atomic spacing of 1.5 × 10-10 m. For strong diffraction, the de Broglie wavelength of the electrons should equal this spacing. Calculate the speed the electrons need. (3)
(c) Calculate the potential difference through which the electrons must be accelerated from rest to reach this speed. (2)
Mass of electron = 9.11 × 10-31 kg
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Key terms in this lesson
- de broglie wavelength
- The wavelength associated with a moving particle, equal to the Planck constant divided by its momentum.
- wave-particle duality
- The idea that particles such as electrons and photons can show both wave-like and particle-like behaviour depending on the situation.
More in Quantum Physics
- Excitation and De-excitation
- Line Spectra
- Exam Question 1
- Exam Question 2
- Exam Question 3
- Exam Question 4
- Exam Question 5
- Exam Question 6
All 21 lessons in Quantum Physics · All Edexcel AS-level Physics topics