Advertisements
Advertisements
प्रश्न
Explain two types of diffraction of light.
उत्तर
The diffraction phenomenon is classified into two types:
1. Fraunhofer diffraction: The source of light and the screen on which the diffraction pattern is obtained are effectively at infinite distance from the diffracting system. In this case, we consider plane wavefront. The diffraction pattern is obtained by using a convex lens.
2. Fresnel diffraction: The source of light and the screen are kept at finite distance from the diffracting system. In this case, we consider a cylindrical or spherical wavefront.
APPEARS IN
संबंधित प्रश्न
What is 'diffraction of light'
In the diffraction pattern due to a single slit of width 'd' with incident light of wavelength 'λ', at an angle of diffraction θ. the condition for first minimum is ....
(a)`lambda sin theta =d`
(b) `d costheta =lambda`
(c)`d sintheta=lambda`
(d) `lambda cos theta=d`
A point is situated at 7cm and 7·2 cm from two coherent sources. Find the· nature of illumination at the point if wavelength of light is 4000A.
For a single slit of width "a", the first minimum of the interference pattern of a monochromatic light of wavelength λ occurs at an angle of λa. At the same angle of λa, we get a maximum for two narrow slits separated by a distance "a". Explain.
Two wavelengths of sodium light of 590 nm and 596 nm are used in turn to study the diffraction taking place at a single slit of aperture 2 × 10−6 m. The distance between the slit and the screen is 1·5 m. Calculate the separation between the positions of first maxima of the diffraction pattern obtained in the two cases.
In Fraunhofer diffraction, how is the angular width of the central bright fringe affected when slit separation is increased?
Two wavelengths of sodium light 590 nm and 596 nm are used, in turn, to study the diffraction taking place due to a single slit of aperture 1 × 10−4 m. The distance between the slit and the screen is 1.8 m. Calculate the separation between the positions of the first maxima of the diffraction pattern obtained in the two cases.
Monochromatic light of wavelength 4300 Å falls on a slit of width ‘a’. For what value of ‘a’ the first maximum falls at 30° ?
What should be the order of obstacle or aperture for diffraction of light?
Wavelength of light of frequency 100 Hz is
The penetration of light into the region of geomaterial shadow is called.
The magnifying power of a telescope in normal adjustment is 24, when the length of the telescope tube 1 meter. The focal length of the eye lens is
Direction of the first secondary maximum in the Fraunhoffer diffraction pattern at a single slit is given by (a is the width of the slit):
Which of the following device is used to study the spectra of light?
Consider the diffraction pattern for a small pinhole. As the size of the hole is increased ______.
- the size decreases.
- the intensity increases.
- the size increases.
- the intensity decreases.
A polariod (I) is placed in front of a monochromatic source. Another polatiod (II) is placed in front of this polaroid (I) and rotated till no light passes. A third polaroid (III) is now placed in between (I) and (II). In this case, will light emerge from (II). Explain.
AC = CO = D, S1C = S2C = d << D
A small transparent slab containing material of µ = 1.5 is placed along AS2 (Figure). What will be the distance from O of the principal maxima and of the first minima on either side of the principal maxima obtained in the absence of the glass slab?
Write two points of difference between an interference pattern and a diffraction pattern.
How can you differentiate whether a pattern is produced by a single slit or double slit?
Derive the expression for the angular position of (i) bright and (ii) dark fringes produced in a single slit diffraction.
In a diffraction pattern due to a single slit, how will the angular width of the central maximum change, if the screen is moved closer to the slit?
Justify your answer.
Draw a labelled graph showing the variation in intensity of diffracted light with diffracting angle in a single slit Fraunhofer diffraction experiment.
