Question

In a YDSE, $\lambda =$5000 A${}^{\circ }$. The distance between slits is 0.2mm and distance between slits and screen is 2m. If central maxima is at x$=$0, the distance of 3rd maxima from central maxima is :

• A. 5 cm
• B. 0.5 cm
• C. 1.67 cm
• D. 1.5 cm

Answer 1

The correct option is D 1.5 cm

Position of $3^{rd}$ maxima
$=\frac{3D\lambda }{d}$
$=\frac{3\times 2\times 5000\times {10}^{-10}}{0.2\times {10}^{-3}}$
$=15\times {10}^{-3}m$
$=1.5cm$