Test Index

NCERT Class XII Chapter
Dual Nature of Radiation and Matter
Questions With Solutions

© examsnet.com
Question : 34
Total: 37
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 Standford, USA. Guess what might have been the order of energy of these electron beams. (Rest mass energy of electron = 0.511 MeV).
Solution:  
∴ Momentum of electron associated with given wavelength
p =
h
λ
 =
.63×10−34Js
10−15m
 = .63 × 10−19kgms−1
Rest mass energy of electron,
m0c2 = 0.511 MeV = 0.511 × 106 × 1.6 × 10–19 J = 0.511 × 1.6 × 10–13 J.
We use the relativistic formula for the energy of electron, i.e.,
E = √c2p2+m02c4
E =
√9×(6.63)2×10−22+(0.511×1.6)2×10−26

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.
© examsnet.com
Go to Question:
Prev Question
Next Question