Question

A small aperture is illuminated with a parallel beam of $\lambda$ = 628nm . The emergent beam has an angular divergence of 2${}^{\circ }$ . The size of the aperture is.

• A. $9\mu m$
• B. $18\mu m$
• C. $27\mu m$
• D. $36\mu m$

Answer 1

Answer: (B)

Correct answer is (b) $18\mu m$