Q. A parallel beam of fast moving electrons is incident normally on a narrow slit. A screen is placed at a large distance from the slit. If the speed of the electrons is increased, which of the following statement is correct
A) Diffraction pattern is not observed on the screen in the case of electrons
B) The angular width of the central maxima of the diffraction pattern will increase
C) The angular width of the central maxima will decrease
D) The angular width of the central maxima will remain the same
Explanation
(c) When the speed of the electrons is increased, the wavelength decreases. The central maxima extends from $- \lambda/a$ to $+ \lambda/a$. As $\lambda$ decreases, the width decreases. The angular width decreases
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.