Question

In a Frounhofer diffraction experiment, a single slit of width $0.5 \,mm$ is illuminated by a monochromatic light of wavelength $600\, nm$. The diffraction pattern is observed on a screen at a distance of $50 \,cm$ from the slit. What will be the linear separation of the first order minima?

• A. 1.0 nm
• B. 1.1 nm
• C. 0.6 mm
• D. 1.2 nm

Answer 1

Answer: (D)

$d=0.5 \,mm$
$\lambda=600 \,nm .$
Width of central maxima $=\frac{2 \lambda D}{d}$
$D=50 \,cm$
$\frac{2 \lambda D}{d}=\frac{2 \times 600 \times 50 \times 10^{-2} \times 10^{-9}}{0.5 \times 10^{-3}}=1.2 \,mm$