Q. Radius of central zone of circular zone plate is $2.3mm$. Wavelength of incident light is $5893\ \mathring{\mathrm{A}}$. Source is at a distance of $6m$. Then the distance of first image will be
A) $9m$
B) $12m$
C) $24m$
D) $36m$
Explanation
(a) $f_{1} = \frac{r^{2}}{\lambda} = \frac{\left( 2.3 \times 10^{- 3} \right)^{2}}{5893 \times 10^{- 10}} = 9m$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.