Q 12-10-095JEE MainJEE Main 2022 (25 Jun, Shift 1)Easy
Two light beams having intensities $I$ and $9I$ interfere to produce a fringe pattern on a screen. The phase difference between the beams is $\dfrac\pi2$ at point $P$ and $\pi$ at point $Q$. Then the difference between the resultant intensities at $P$ and $Q$ will be:
Answer: (B) $6I$
$I_R = I_1 + I_2 + 2\sqrt{I_1I_2}\cos\phi = 10I + 6I\cos\phi$.
At $P$: $I_P = 10I$. At $Q$: $I_Q = 10I - 6I = 4I$. Difference $= 6I$.
Solution by Sreeraj P, M.Sc Physics