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Set 5 of 10 · Questions 121-150 of 295

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JEE Main Physics · Wave Optics · Set 5 (Q121-150)

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  1. 121.
    For light diverging from a finite point source
    1. (1)the wave front is parabolic
    2. (2)the wave front is cylindrical
    3. (3)the intensity at the wave front does not depend on the distance
    4. (4)the intensity decreases in proportion to the distance squared.
  2. 122.
    The value of numerical aperature of the objective lens of a microscope is If light of wavelength is used, the minimum separation between two points, to be seen as distinct, will be:
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  3. 123.
    The shape of wavefront of light diverging from point source
    1. (1)spherical
    2. (2)planar
    3. (3)cylindrical
    4. (4)circular
  4. 124.
    If the two slits in Young's double slit experiment are of unequal width, then
    1. (1)the bright fringes will have unequal spacing
    2. (2)the bright fringes will have unequal brightness
    3. (3)the fringes do not appear
    4. (4)the dark fringes are not perfectly dark.
  5. 125.
    When light propagates through a given homogeneous medium, the velocities of
    1. (1)primary wave front are larger than those of secondary wavelets.
    2. (2)primary wave fronts are lesser than those of secondary wavelets.
    3. (3)primary wave fronts are greater than or equal to those of secondary wavelets.
    4. (4)primary wave front and wavelets are equal.
  6. 126.
    A plane wave front of wavelength is incident on a single slit of width . The angular width of principal maximum is
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  7. 127.
    Critical angle for certain medium is . The polarizing angle of that medium is
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  8. 128.
    The Young's double slit interference experiment is performed using light consisting of 480
    nm and 600 nm wavelengths to form interference patterns. The least number of the bright fringes of 480 nm light that are required for the first coincidence with the bright fringes formed by 600 nm light is
    1. (1)5
    2. (2)4
    3. (3)6
    4. (4)8
  9. 129.
    In a double-slit experiment, at a certain point on the screen the path difference between the two interfering waves is th of a wavelength. The ratio of the intensity of light at that point to that at the center of a bright fringe is :
    1. (1)0.568
    2. (2)0.760
    3. (3)0.853
    4. (4)0.672
  10. 130.
    If the ratio of the intensities of two waves producing interference is , then the ratio of the resultant maximum intensity to minimum intensity will be
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  11. 131.
    In a Young's double slit experiment, if the wavelength of light is increased by and the distance between the slits is doubled then the percentage change in fringe width is
    1. (1)75
    2. (2)50
    3. (3)25
    4. (4)15
  12. 132.
    Visible light of wavelength falls normally on single slit and produces a diffraction pattern. It is found that the second diffraction minimum is at from the central maximum. If the first minimum is produced at , then is close to:
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  13. 133.
    The property of light which cannot be explained by Huygen's construction of wavefront is
    1. (1)Refraction
    2. (2)Reflection
    3. (3)Diffraction
    4. (4)Origin of spectra
  14. 134.
    Young's double slit experiment is carried out by using green, red and blue light, one colour at a time. The fringe width recorded are respectively, then
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  15. 135.
    If the source of light used in a Young's double slit experiment is changed from red to violet:
    1. (1)the fringes will become brighter.
    2. (2)consecutive fringe lineswill come closer.
    3. (3)the central bright fringe will become a darkfringe.
    4. (4)the intensity of minima will increase.
  16. 136.
    The critical angle of a certain medium is The polarizing angle of the medium is
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  17. 137.
    An unpolarised beam of intensity is incident on a pair of nicols making an angle of with each other. The intensity of light emerging from the pair is
    1. (1)
    2. (2)
    3. (3)
    4. (4).
  18. 138.
    In a system of two crossed polarisers, it is found that the intensity of light from the second polariser is half from that of first polariser. The angle between their pass axes is
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  19. 139.
    In Young's double slit experiment, point on the screen has a path difference of and point on the screen has a path difference of . What is the ratio of the intensities at point to ?
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  20. 140.
    In a Young's double slit experiment with slit separation one observes a bright fringe at angle by using light of wavelength When the light of wavelength is used a bright fringe is seen at the same angle in the same set up. Given that and are in visible range to, their values are:
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  21. 141.
    When a polaroid sheet is rotated between two crossed polaroids then the transmitted light intensity will be maximum for a rotation of:
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  22. 142.
    A single slit Fraunh offer diffraction pattern is formed with white light. For what wavelength of light, the third secondary maximum in the diffraction pattern coincides with the second secondary maximum in the pattern for red light of wavelength ?
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  23. 143.
    Through a narrow slit of width , diffraction pattern is formed on a screen kept at a distance from the slit. The wavelength of the light used is and falls normal to the slit and screen. Then, the distance between the two minima on either side of the central maximum is
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  24. 144.
    An unpolarized light of intensity is passed through two polaroids kept one after the other with their planes parallel to each other. The intensity of light emerging from second polaroid is . The angle between the pass axes of the polaroid is
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  25. 145.
    Resolving power of telescope increases when
    1. (1)wavelength of light decreases
    2. (2)wavelength of light increases
    3. (3)focal length of eye piece increases
    4. (4)foeal length of eye piece decreases
  26. 146.
    A monochromatic light of wavelength is incident on the single slit of width . If the diffraction pattern is formed at the focus of the convex lens of focal length , the linear width of the central maximum is :
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  27. 147.
    In a single slit diffraction, the slit is illuminated with light of wavelength . If the slit were illuminated by a light of wavelength the angular width of the central maximum decreases by . Then is
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  28. 148.
    Two coherent monochromatic light beams of intensities I and 4 I are superimposed. The difference between maximum and minimum possible intensities in the resulting beam is . The value of is ______
  29. 149.
    In two separate Young's double-slit experimental set-ups and two monochromatic light sources of different wavelengths are used to get fringes of equal width. The ratios of the slits separations and that of the wavelengths of light used are and respectively. The corresponding ratio of the distances between the slits and the respective screens ( ) is .
  30. 150.
    A parallel beam of monochromatic light of wavelength 600 nm passes through single slit of 0.4 mm width. Angular divergence corresponding to second order minima would be ______.