Q. An electron microscope is used to probe the atomic arrangement to a resolution of $5\ \mathring{\mathrm{A}}.$ What should be the electric potential to which the electrons need to be accelerated
A) $2.5\ V$
B) $6\ V$
C) $2.5\ kV$
D) $5\ kV$
Explanation
(b) Minimum wavelength $= 5\mathring{\mathrm{A}}$
$\lambda = \frac{12.2\ \mathring{\mathrm{A}}}{\sqrt{V}} = 5\mathring{\mathrm{A}}$
Acceleration potential $= 6.25\ V$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.