Diffraction - NEET Physics Questions
Question 1: moderate

A parallel beam of light of wavelength 6000 Å is incident normally on a slit of width 0.2 mm .
The diffraction pattern is observed on a screen which is placed at the focal plane of a convex lens of focal length 50 cm . If the lens is placed close to the slit, the distance between the minima on both sides of the central maximum will be

1. 1 mm
2. 2 mm
3. 3 mm
4. 4 mm
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Question 2: moderate

Light of wavelength 600 nm is incident upon a single slit with width \[4\times 10^{-4} m\] . The figure shows the pattern observed on a screen positioned 2 m from the slits . Determine the distance s.

1. 0.002 m
2. 0.003 m
3. 0.004 m
4. 0.006 m
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Question 3: moderate

The ratio of intensities of consecutive maxima in the diffraction pattern due to a single slit is :

1. 1 : 4 : 9
2. 1 : 2 : 3
3. \[1:\frac{4}{9\pi^{2}}:\frac{4}{25\pi^{2}}\]
4. \[1:\frac{1}{\pi^{2}}:\frac{9}{\pi^{2}}\]
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Question 4: easy

Consider Fraunhoffer diffraction pattern obtained with a single slit at normal incidence. At the angular position of first diffraction minimum, the phase difference between the wavelets from the opposite edges of the slit is :

1. π/4
2. π/2
3. π
4.
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Question 5: easy

A single slit of width 0.20 mm is illuminated with light of wavelength 500 nm. The observing screen is placed 80 cm from the slit. The width of the central bright fringe will be :

1. 1 mm
2. 2 mm
3. 4 mm
4. 5 mm
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Question 6: moderate

A plane wavefront \[\left( \lambda=6\times 10^{-7}m \right)\] falls on a slit 0.4 mm wide. A convex lens of focal length 0.8m placed behind the slit focusses the light on a screen. What is the linear diameter of second maximum :

1. 6 mm
2. 12 mm
3. 3 mm
4. 9 mm
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Question 7: moderate

For what distance is ray optics a good approximation when the aperture is 4 mm wide and the wavelength is 500 nm :

1. 32 m
2. 64 m
3. 16 m
4. 8 m
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Question 8: moderate

A light wave is incident normally over a slit of width \[24\times 10^{-5} cm\]. The angular position of second dark fringe from the central maxima is 30 degree. What is the wavelength of light :

1. 6000 Å
2. 5000 Å
3. 3000 Å
4. 1500 Å
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Question 9: moderate

In the far field diffraction pattern of a single slit under polychromatic illumination, the first minima with the wavelength λ1 is found to be coincident with the third maximum at λ2. So :

1. 3λ1 = 0.3λ2
2. 3λ1 = λ2
3. λ1 = 3.5λ2
4. 0.3λ1 = 3λ2
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Question 10: moderate

A single slit of width a is illuminated by violet light of wavelength 400 nm and the width of the diffraction pattern is measured as y. When half of the slit width is covered and illuminated by yellow light of wavelength 600 nm, the width of the diffraction pattern is :

1. The pattern vanishes and the width is zero
2. y/3
3. 3y
4. None of these
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