Physics Dawn of Modern Physics PMDC 2020
PMDC Verified Question 41 of 52
The wavelength associated with an electron is of the order of:
A
Visible light
B
X-Rays
C
Radio waves
D
Infrared
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: X-Rays
Concept:

Accelerated electrons in standard practical scenarios (like cathode ray tubes or electron microscopes) possess sufficient momentum to yield highly compressed wavelengths.

Formula:

$$ \lambda = \frac{h}{p} $$

Solution:

  • Typical kinetic energies for experimental electrons are in the range of eV to keV.


  • This corresponds to de Broglie wavelengths in the range of \( 10^{-10} \text{ m} \) to \( 10^{-12} \text{ m} \).


  • This length scale coincides exactly with the electromagnetic wavelength range of X-rays (Angstrom scale).


Why other options are incorrect:

Visible light (400-700 nm), Infrared, and Radio waves all have substantially longer, macroscopic wavelengths that a fast-moving fundamental particle would not exhibit.

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