Question

Assertion :Two point coherent sources of light $S_1$ and $S_2$ are placed on a line as shown. $P$ and $Q$ are two points on that line. If at point $P$ maximum intensity is observed then maximum intensity should also be observed at Q. Reason: In the figure of assertion the distance $|S_{1}P-S_{2}P|$ is equal to distance $|S_{2}Q-S_{1}Q|$.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is B Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

If maximum intensity is observed at $P$ then for maximum intensity to be also observed at $Q,S_1$ and $S_2$ must have phase difference of $2m\pi$ (where $m$ is an integer).