Question

A diffraction pattern is obtained using a beam of red light. What happens if the red light is replaced by blue light?

• A. No change.
• B. Diffraction bands become narrower and crowded together.
• C. Band become broader and father apart.
• D. Band disappears altogether.

Answer 1

Answer: (B)

Diffraction bands become narrower and crowded together.

Answer 2

As $\lambda_{blue} < \lambda_{red,}$ and width of diffraction bands is directly proportional to $\lambda$, therefore diffraction bands become narrower and crowded.