Davisson-Germer Experiment - UNSOLVED PRACTICE SET

Q7. Describe the basic setup of the Davisson-Germer experiment. What was being measured?

Q8. Why was a nickel crystal used in the Davisson-Germer experiment? What role did the crystal play?

Q9. How does the Davisson-Germer experiment confirm the wave nature of electrons?

Q10. What was the accelerating voltage used in the Davisson-Germer experiment, and what was the corresponding de Broglie wavelength of the electrons?

Q11. Compare the Davisson-Germer experiment with the experiment performed by G.P. Thomson. How did both contribute to the acceptance of matter waves?

Q12. Why was the Davisson-Germer experiment conducted with electrons rather than heavier particles like protons?

Q13. Describe the Davisson-Germer experiment in detail. Explain how the experimental setup was designed to detect electron diffraction and what observations were made.

Q14. Explain how the results of the Davisson-Germer experiment provide direct evidence for de Broglie's hypothesis. Discuss the significance of the angle of diffraction and how it relates to the de Broglie wavelength.

Q15. Compare the Davisson-Germer experiment with Bragg's X-ray diffraction experiment. Discuss the similarities in the physical principles and the mathematical treatment of both experiments.

Q16. In the Davisson-Germer experiment, electrons were accelerated through a potential difference of 54 V.

(a) Calculate the kinetic energy of the electrons in eV.

(b) Calculate the de Broglie wavelength of these electrons.

(c) The first diffraction maximum was observed at an angle of 50° with respect to the incident beam. Using Bragg's law (2d sin θ = nλ), calculate the interatomic spacing d in the nickel crystal.

(d) Compare the calculated de Broglie wavelength with the known interatomic spacing in nickel (about 0.215 nm)

Q17. An electron microscope uses electrons accelerated through 50 kV to study the structure of a crystal.

(a) Calculate the de Broglie wavelength of these electrons.

(b) If the interatomic spacing in the crystal is 0.2 nm, calculate the angle at which the first-order diffraction maximum would be observed.

(c) Compare the resolving power of this electron microscope with that of an optical microscope using light of wavelength 500 nm.

Q18. In your school's physics exhibition, a student creates a display about the Davisson-Germer experiment and its impact.

(a) She calculates that electrons accelerated through 100 V have a de Broglie wavelength of about 0.123 nm. Verify this calculation.

(b) She explains that this wavelength is comparable to X-ray wavelengths. Calculate the energy of X-ray photons with this same wavelength and compare it with the kinetic energy of the electrons.

(c) The student sets up a thought experiment: if protons were used instead of electrons, accelerated through the same 100 V, what would be their de Broglie wavelength? Would the diffraction pattern be easier or harder to observe? Explain.

(d) A classmate asks why the Davisson-Germer experiment is considered more significant than de Broglie's theoretical hypothesis. Present your argument explaining the importance of experimental verification in physics.

(e) In modern India, electron diffraction is used in materials science research at institutions like IITs to study crystal structures. Explain why electron diffraction is preferred over X-ray diffraction for studying very small crystals or thin films.