Neet Solved Paper 2013 Question 42
Question: A parallel beam of fast moving electrons is incident normally on a narrow slit. A fluorescent screen is placed at a large distance from the slit. If the speed of the electrons is increased, then which of the following statements is correct?
Options:
A) Diffraction pattern is not observed on the screen in the case of electrons
B) The angular width of the central maximum of the diffraction pattern will increase
C) The angular width of the central maximum will decrease
D) The angular width of the central maximum will be unaffected
Show Answer
Answer:
Correct Answer: B
Solution:
- We know that $ \lambda =\frac{h}{mv}$ Also for angular width ω=2λd
So we can say ω ∝ λ ∝ $\frac{1}{v}$ .So if the velocity increases, the angular width of the central maximum will decrease.
