Q.
In Young’s double slit experiment, the intensity on screen at a point where path difference is $\lambda$ is $K$. What will be intensity at the point where path difference is $/4$ ?
A) $K/4$
B) $K/2$
C) $K$
D) $zero$
Explanation
(b) When path difference is $\lambda,\ I_{\max} = 4I = K$
When path difference is $\frac{\lambda}{4}$, phase difference, $\phi = \pi/2$
$\therefore\ \ I_{R} = I_{1} + I_{2} + 2\sqrt{I_{1}I_{2}}\cos\phi$
$= I + I = 2I = \frac{K}{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.