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QNEET-2016-Ph-1140: NEET 2016 Physics - Class 12 NEET-2016-Ph-1140 Solution: A linear aperture whose width is 0.02 cm is placed immediately…
A linear aperture whose width is 0.02 cm is placed immediately in front of a lens of focal length 60 cm. The aperture is illuminated normally by a parallel beam of wavelength . The distance of the first dark band of the diffraction pattern from the centre of the screen is 0.10 cm 0.25 cm 0.20 cm 0.15 cm
Multiple Choice Options
- A 0.10 cm
- B 0.25 cm
- C 0.20 cm
- D 0.15 cm
Step-by-Step Verified Solution
Here, a = 0.02 cm = 2 _ 10 �4 m
_ = 5 _ 10 �5 cm = 5 _ 10 �7 m
D = 60 cm = 0.6 m
Position of first minima on the diffraction pattern,
y 1 = D _ a
= 0.6 _ 5 _ 10 _ 7 2 _ 10 _ 4 = 15 _ 10 -4 m = 0.15 cm