MHT CET · Physics · Wave Optics

A diffraction pattern is obtained using a beam of red light. If red light is replaced by blue light then

A no change in diffraction pattern.
B diffraction bands become narrow and crowded together.
C diffraction bands become broader and farther apart.
D bands disappear.

Verified Solution

Answer & Solution

Correct Answer

(B) diffraction bands become narrow and crowded together.

Step-by-step Solution

Detailed explanation

For diffraction, Distance between successive maxima is given
\(\begin{aligned}
& \text { by, } \beta=\frac{\lambda \mathrm{D}}{\mathrm{a}} \Rightarrow \beta \propto \lambda \\
& \lambda_{\text {blue }} \lt \lambda_{\text {red }}
\end{aligned}\)
\(\therefore \quad\) The diffraction bands become narrow and crowded together.

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

Explore more questions on app

From MHT CET

Explore more questions on app