Q. In Young’s double slit experiment, if the widths of the slits are in the ratio 4 : 9, the ratio of the intensity at maxima to the intensity at minima will be
A) 169 : 25
B) 81 : 16
C) 25 : 1
D) 9 : 4
Explanation
(c) Slit width ratio $= 4:9$; hence $I_{1}:I_{2} = 4:9$
$\therefore\frac{a_{1}^{2}}{a_{2}^{2}} = \frac{4}{9} \Rightarrow \frac{a_{1}}{a_{2}} = \frac{2}{3}$
$\therefore\frac{I_{\max}}{I_{\min}} = \frac{\left( a_{1} + a_{2} \right)^{2}}{\left( a_{1} - a_{2} \right)^{2}} = \frac{25}{1}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.