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प्रश्न
Explain experimental setup for Fraunhofer diffraction with neat diagram.
उत्तर
- Set up for Fraunhofer diffraction has a monochromatic source of light S at the focus of a converging lens. Ignoring aberrations, the emerging beam will consist of plane parallel rays resulting in-plane wavefronts.
- These are incidents on the diffracting element such as a slit, a circular aperture, a double slit, a grating, etc.
- In the case of a circular aperture, S is a point source and the lenses are bi-convex. For linear elements like slits, grating, etc., the source is linear and the lenses are cylindrical in shape so that the focussed image is also linear.
Set up for Fraunhofer diffraction - An emerging beam is an incident on another converging lens that focuses the beam on a screen.
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संबंधित प्रश्न
In a biprism experiment, the fringes are observed in the focal plane of the eyepiece at a distance of 1.2 m from the slits. The distance between the central bright and the 20th bright band is 0.4 cm. When a convex lens is placed between the biprism and the eyepiece, 90 cm from the eyepiece, the distance between the two virtual magnified images is found to be 0.9 cm. Determine the wavelength of light used.
What must be the ratio of the slit width to the wavelength of light for a single slit to have the first diffraction minimum at 45.0°?
In a single slit diffraction pattern, the first minima obtained with the red light of wavelength 6600 A.U. coincides with the first maxima f some other wavelength λ then is ______
What is the difference between Fresnel and Fraunhofer diffraction?
Compare Young’s Double Slit Interference Pattern and Single Slit Diffraction Pattern.
Explain Fraunhofer diffraction at a single slit with a neat ray diagram. Obtain an expression for the width of the central bright fringe.
In diffraction experiment, from a single slit, the angular width of the central maxima does not depend upon ____________.
In biprism experiment, the distance between source and eyepiece is 1.2 m, the distance between two virtual sources is 0.84 mm. Then the wavelength of light used if eyepiece is to be moved transversely through a distance of 2.799 cm to shift 30 fringes is ______.
A lens having focal length f gives Fraunhofer type diffraction pattern of a slit having width a. If wavelength of light is λ, the distance of first dark band and next bright band from axis is given by ____________.
A diffraction is obtained by using a beam of yellow light. What will happen if the yellow light is replaced by the red light?
A slit of width a is illuminated by white light. For red light `(λ = 6500 Å)`, the first minima is obtained at θ = 60°. Then the value of a will be ______.
In Fraunhofer diffraction pattern, slit width is 0.2 mm and screen is at 4 m away from the lens. If wavelength of light used is 5500 Å, then the distance between the first minimum on either side of the central maximum is (`theta` is small and measured in radian) ____________.
In a single slit diffraction pattern, which of the following is incorrect for fringe pattern?
In a single slit diffraction experiment, first minimum for a light of wavelength 480 nm coincides with the first maximum of another wavelength `lambda.` Then `lambda'` is ____________.
Select the CORRECT statement from the following.
The first minimum of a single slit diffraction pattern is observed at angle 2° with a light of wavelength 510 nm. The width of this slit is ____________.
When two coherent sources in Young's experiment are far apart, then interference pattern ______
A parallel beam of monochromatic light of wavelength 5 × 10-7 m is incident normally on a single narrow slit of width 10-3 mm. At what angle of diffraction, the first minima are observed?
A physical quantity P is described by the relation p = a1/2 b2 c3 d-4. If the relative errors in the measurement of a, b, c and d respectively, are 2%, 1%, 3% and 5%, then the relative error in P will be ______.
The increase in energy of a metal bar of length 'L' and cross-sectional area 'A' when compressed with a load 'M' along its length is ______.
(Y = Young's modulus of the material of metal bar)
In Fraunhofer diffraction pattern, slit width is 0.2 mm and screen is at 2 m away from the lens. If wavelength of light used is 5000 Å, then the distance between the first minimum on either side of the central maximum is ______. (θ is small and measured in radian)
Let a steel bar of length l, breadth b and depth d be loaded at the centre by a load W. Then the sag of bending of beam is ______.
(Y = Young's modulus of material of steel)
The angular separation of the central maximum in the Fraunhofer diffraction pattern is measured. The slit is illuminated by the light of wavelength 6000 Å. If the slit is illuminated by light of another wavelength, the angular separation decreases by 30%. The wavelength of light used is ______.
In a Young's double slit experiment carried out with light of wavelength λ = 5000 Å, the distance between the slits is 0.2 mm and the screen is at 200 cm from the slits. The central maximum is at x = 0. The third maximum (taking the central maximum as zeroth maximum) will be at x equal to ______.
The angular width of the central maximum of the diffraction pattern in a single slit (of width a) experiment, with λ as the wavelength of light, is ______.
In a double slit interference experiment, the distance between the slits is 0.05 cm and screen is 2 m away from the slits. The wavelength of light is 6000 Å. The distance between the fringes is ______.
In a biprism experiment, the slit is illuminated by red light of wavelength 6400 A and the crosswire of eyepiece is adjusted to the centre of 3rd bright band. By using blue light it is found that 4th bright band is at the centre of the cross wire. Calculate the wavelength of blue light.
Using the geometry of the double slit experiment, derive the expression for fringe width of interference bands.
