STANDARDPhysics-Wave Optics
STANDARD Physics Diffraction MCQ Question
Type: MCQ-numerical-Medium-Class 12
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
Correct Answer
Option A
Detailed Explanation
The width of the slit can be calculated using the formula for the position of the first minima in a single-slit diffraction pattern: d = nλD/x. Here, n = 1, λ = 500 nm = 500 x 10⁻⁹ m, D = 1 m, and x = 2.5 mm = 2.5 x 10⁻³ m. Substituting these values gives d = 0.2 mm.
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