Question 34: NCERT Solutions for 12th Class Physics: Chapter 11-Dual Nature of Radiation and Matter
The wavelength of a probe is roughly a measure of the size of a structure that it can probe in some detail. The quark structure of protons and neutrons appears at the minute length scale of 10-15 m or less. This structure was first probed in early 1970’s using high energy electron beam produced by a linear accelerator at Stand ford, USA. Guess what might have been the order of energy of these electron beams. (Rest mass energy of electron = 0.511 M eV).
Solution:
Momentum of electron associated with given wavelength
Second term showing rest mass energy is negligible. Energy, E = 1.989 × 10-10 J = 1.24 BeV Thus, energies acquired by electron from the given accelerator must have been of the order of a few BeV.
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NCERT Solutions for 12th Class Physics: Chapter 11-Dual Nature of Radiation and Matter