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Fresnel diffraction is produced due to light rays falling on a small obstacle. The intensity of light at a point on a screen beyond an obstacle depends on

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Important Questions on Wave Optics

EASY
Physics>Optics>Wave Optics>Fresnel Diffraction
In a diffraction pattern due to a single slit of width a the first minimum is observed at an angle 30o when light of wavelength 5000 Å is incident on the slit. The first secondary maximum is observed at an angle of:
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Physics>Optics>Wave Optics>Fresnel Diffraction
Light travels in a straight line because
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Physics>Optics>Wave Optics>Fresnel Diffraction
The speed of electrons in a scanning electron microscope is 1×107 ms-1. If the protons having the same speed are used instead of electrons, then the resolving power of scanning proton microscope will be changed by a factor of:
MEDIUM
Physics>Optics>Wave Optics>Fresnel Diffraction
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 5×10-5 cm. The distance of the first dark band of the diffraction pattern from the centre of the screen is
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Physics>Optics>Wave Optics>Fresnel Diffraction
What do you understand by diffraction? Write the difference between diffraction and interference.
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Physics>Optics>Wave Optics>Fresnel Diffraction
A parallel beam of electrons travelling in x - direction falls on a slit of width d (see figure). If after passing the slit, an electron acquires momentum py in the y - direction then for a majority of electrons passing through the slit (h is Planck's constant):

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Physics>Optics>Wave Optics>Fresnel Diffraction

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A : An electron microscope can achieve better resolving power than an optical microscope.

Reason R : The de Broglie's wavelength of the electrons emitted from an electron gun is much less than wavelength of visible light.

In the light of the above statements, choose the correct answer from the options given below:

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Physics>Optics>Wave Optics>Fresnel Diffraction
The angular width of the central maximum in a single slit diffraction pattern is 60° . The width of the slit is 1 μm. The slit is illuminated by monochromatic plane waves. If another slit of the same width is made near it, Young's fringes can be observed on a screen placed at a distance 50 cm from the slits. If the observed fringe width is 1 cm, what is slit separation distance? (i.e., the distance between the centres of each slit.)
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Physics>Optics>Wave Optics>Fresnel Diffraction
Write any two differences between and interference of light.
MEDIUM
Physics>Optics>Wave Optics>Fresnel Diffraction
Write four differences between interference and diffraction.
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Physics>Optics>Wave Optics>Fresnel Diffraction
A parallel beam of light of wavelength 4000 A∘ passes through a slit of width 5×10-3 m. The angular spread of the central maxima in the diffraction pattern is
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Physics>Optics>Wave Optics>Fresnel Diffraction
For what distance is ray optics a good approximation when the aperture is 4 mm wide and the wavelength is 500 nm ?
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Physics>Optics>Wave Optics>Fresnel Diffraction
A single slit of width b is illuminated by a coherent monochromatic light of wavelength λ. If the second and fourth minima in the diffraction pattern at a distance 1 cm from the slit are at 3 cm and 6 cm respectively from the central maximum, what is the width of the central maximum? (i.e. distance between first minimum on either side of the central maximum)
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Physics>Optics>Wave Optics>Fresnel Diffraction
At the first minimum adjacent to the central maximum of a single-slit diffraction pattern, the phase difference between the Huygen's wavelet from the edge of the slit and the wavelet from the midpoint of the slit is:
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Physics>Optics>Wave Optics>Fresnel Diffraction
A single slit of width 0.1 mm is illuminated by a parallel beam of light of wavelength 6000 Å and diffraction bands are observed on a screen 0.5 m from the slit. The distance of the third dark band from the central bright band is:
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Physics>Optics>Wave Optics>Fresnel Diffraction
A beam of light of λ=600 nm from a distant source falls on a single slit 1 mm wide and the resulting diffraction pattern is observed on a screen 2 m away. The distance between first dark fringes on either side of the central bright fringe is:
MEDIUM
Physics>Optics>Wave Optics>Fresnel Diffraction
The box of a pin hole camera, of length L, has a hole of radius a. It is assumed that when the hole is illuminated by a parallel beam of light of wavelength λ the spread of the spot (obtained on the opposite wall of the camera) is the sum of its geometrical spread and the spread due to diffraction. The spot would then have its minimum size (say bmin ) when:
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Physics>Optics>Wave Optics>Fresnel Diffraction
Two poles are separated by a distance of 3.14 m The resolving power of human eye is 1minute of an arc. The maximum distance from which he can identify the two poles distinctly is
MEDIUM
Physics>Optics>Wave Optics>Fresnel Diffraction
 Describe any two characteristic features which distinguish between interference and diffraction phenomena. Derive the expression for the intensity at a point of the interference pattern in Young’s double slit experiment.
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Physics>Optics>Wave Optics>Fresnel Diffraction
For what distance the ray optics will be a good approximation when the aperture is 5 mm wide and the wavelength is 450 nm?