Q. In Young’s double slit experiment, when two light waves form third minimum, they have
A) Phase difference of $3\pi$
B) Phase difference of $\frac{5\pi}{2}$
C) Path difference of $3\lambda$
D) Path difference of $\frac{5\lambda}{2}$
Explanation
(d) For minima, path difference $\mathrm{\Delta} = (2n - 1)\frac{\lambda}{2}$
For third minima $n = 3 \Rightarrow \mathrm{\Delta} = (2 \times 3 - 1)\frac{\lambda}{2} = \frac{5\lambda}{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.