Q. Plane microwaves are incident on a long slit having a width of 5 cm. The wavelength of the microwaves if the first minimum is formed at $30{^\circ}$ is
A) 2.5 cm
B) 2 cm
C) 25 cm
D) 2 mm
Explanation
(a) As, $a\sin{\theta = n\lambda}$
$\lambda = \frac{a\sin\theta}{n} = \frac{5\sin{30{^\circ}\ }}{1} = 2.5\ cm$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.