Question

What will be the angle of diffracting for the first minimum due to Fraunhoffer diffraction with sources of light of wave length 550 nm and slit of width 0.55 mm.

• A. 0.001 rad
• B. 0.01 rad
• C. 1 rad
• D. 0.1 rad

Answer 1

Answer: (A)

0.001 rad

Answer 2

Using $d\sin\theta = n\lambda,$ for n =1

$\sin\theta = \frac{\lambda}{d} = \frac{550 \times 10^{- 9}}{0.55 \times 10^{- 3}} = 10^{- 3} = 0.001\mspace{6mu} rad$