Question

The condition for diffraction of $mth$ order minima is

• A. $d\sin {\theta }_m=m\lambda ,m=1,2,3,....$
• B. $d\sin {\theta }_m=\frac{m\lambda ,}{2}m=1,2,3,....$
• C. $d\sin {\theta }_m=(m+1)\frac{\lambda }{2},m=1,2,3,....$
• D. $d\sin {\theta }_m=(m-1)\frac{\lambda }{2},m=1,2,3,....$

Answer 1

The correct option is A $d\sin {\theta }_m=m\lambda ,m=1,2,3,....$

For obtaining $mth$ secondary minima at a point on screen, path difference between the diffracted waves, $△=d\sin {\theta }_m=\pm m\lambda$ where, $m=1,2,3,.....$