A parallel beam of light of wavelength 500 nm falls on a narrow slit and the resulting diffraction pattern is observed on a screen 1 m away. It is observed that the first minima is at a distance of 2.5 mm from the centre of the screen. The width of the slit is

Question

A parallel beam of light of wavelength 500 nm falls on a narrow slit and the resulting diffraction pattern is observed on a screen 1 m away. It is observed that the first minima is at a distance of 2.5 mm from the centre of the screen. The width of the slit is (A) 0.2 mm (B) 1 mm (C) 2 mm (D) 1.5 mm

Tardigrade Admin · Accepted Answer

Width of slit, d = (nλ D/x) Here, n = 1, D = 1 m, x = 2.5 mm = 2.5 × 10-3 m λ = 500 nm = 500× 10-9m ∴ d = (1× 500× 10-9× 1/2.5× 10-3) =2 × 10-4 m = 0.2 mm

Q. A parallel beam of light of wavelength $500 nm$ falls on a narrow slit and the resulting diffraction pattern is observed on a screen $1 m$ away. It is observed that the first minima is at a distance of $2.5 mm$ from the centre of the screen. The width of the slit is

$0.2 mm$

$1 mm$

$2 mm$

$1.5 mm$

Width of slit, $d = \frac{nλ D}{x}$
Here, $n = 1, D = 1 m$ ,
$x = 2.5 mm = 2.5 \times 1 0^{- 3} m$
$λ = 500 nm = 500 \times 1 0^{- 9} m$
$∴ d = \frac{1 \times 500 \times 1 0 ^{- 9} \times 1}{2.5 \times 1 0 ^{- 3}}$
$= 2 \times 1 0^{- 4} m = 0.2 mm$

Q. A parallel beam of light of wavelength 500nm falls on a narrow slit and the resulting diffraction pattern is observed on a screen 1m away. It is observed that the first minima is at a distance of 2.5mm from the centre of the screen. The width of the slit is

0.2mm

1mm

2mm

1.5mm