Question

A beam of light of wavelength 600 nm from a distant source falls on a single slit 1 mm wide and the resulting diffraction pattern is observed on a screen 2m away. The distance between the first dark fringes on either side of the central bright fringe is –

• A. 1.2 cm
• B. 1.2mm
• C. 2.4 cm
• D. 2.4 mm

Answer 1

Answer: (D)

2.4 mm

Answer 2

$\frac{2D\lambda}{a} = \frac{2 \times 600 \times 10^{- 9} \times 2}{10^{- 3}}$= 2.4 × 10^–3 m = 2.4mm