Q. The intensity ratio of two coherent sources of light is $p$. They are interfering in some region and produce interference pattern. Then the fringe visibility is
A) $\frac{1 + p}{2\sqrt{p}}$
B) $\frac{2\sqrt{p}}{1 + p}$
C) $\frac{p}{1 + p}$
D) $\frac{2p}{1 + p}$
Explanation
(b) Visibility $V = \frac{I_{\max} - I_{\min}}{I_{\max} + I_{\min}} = \frac{2\sqrt{I_{1}I_{2}}}{\left( I_{1} + I_{2} \right)}$
$= \frac{2\sqrt{I_{1}/I_{2}}}{\left( \frac{I_{1}}{I_{2}} + 1 \right)} = \frac{2\sqrt{P}}{(P + 1)}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.