Class 12 Wave Optics CBSE Questions & Answers

Class 12 · Wave Optics

This is Physics Class 12 Wave Optics CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
Two coherent monochromatic light beams of intensities I and 4I are superposed. The maximum and minimum possible intensities in the resulting beam are
  • A
    5I and 2I
  • B
    9I and I
    Correct
  • C
    5I and I
  • D
    5I and 3I
2
In a young’s double slit experiment using identical slits the intensity at a bright fringe is \({{\rm{I}}_0}\). If one of the slits is now covered, the intensity at any point on the screen will be
  • A
    \({l_0}\)/2
  • B
    \({l_0}\)/4
    Correct
  • C
    \({l_0}\)
  • D
    \({l_0}\)/3
3
In a young’s double slit experiment, the central bright fringe can be identified by
  • A
    using white light instead of monochromatic light
    Correct
  • B
    as it is has greater intensity than other bright fringes
  • C
    as it is narrower than other bright fringes
  • D
    as it is wider than other bright fringes
4
In a young’s double slit experiment, if the slits are of unequal width
  • A
    fringes will not be formed
  • B
    the positions of minimum intensity will not be completely dark
    Correct
  • C
    distance between two consecutive bright fringes will not be equal to the distance between two dark fringes.
  • D
    bright fringe will not be formed at the center
5
A beam of light has a wavelength of 650 nm in vacuum. What is the speed of this light in a liquid whose index of refraction at this wavelength is 1.47
  • A
    2.04 \( \times {\rm{ 1}}{0^{\rm{8}}}{\rm{m }}{{\rm{s}}^{-{\rm{1}}}}\)
    Correct
  • B
    2.1 \( \times {\rm{ 1}}{0^{\rm{8}}}{\rm{m }}{{\rm{s}}^{-{\rm{1}}}}\)
  • C
    2.3 \( \times {\rm{ 1}}{0^{\rm{8}}}{\rm{m }}{{\rm{s}}^{-{\rm{1}}}}\)
  • D
    2.2 \( \times {\rm{ 1}}{0^{\rm{8}}}{\rm{m }}{{\rm{s}}^{-{\rm{1}}}}\)
6
A beam of light has a wavelength of 650 nm in vacuum. What is the wavelength of these waves in the liquid whose index of refraction at this wavelength is 1.47?
  • A
    442nm
    Correct
  • B
    462nm
  • C
    452nm
  • D
    472nm
7
A light beam travels at 1.94 \( \times {\rm{ 1}}{0^{\rm{8}}}{\rm{m }}{{\rm{s}}^{-{\rm{1}}}}\) in quartz. The wavelength of the light in quartz is 355 nm. What is the index of refraction of quartz at this wavelength?
  • A
    1.55
    Correct
  • B
    1.35
  • C
    1.25
  • D
    1.45
8
A light beam travels at 1.94 \( \times {\rm{ 1}}{0^{\rm{8}}}{\rm{m }}{{\rm{s}}^{-{\rm{1}}}}\) in quartz. The wavelength of the light in quartz is 355 nm. If this same light travels through air, what is its wavelength there?
  • A
    550nm
    Correct
  • B
    580nm
  • C
    600nm
  • D
    620nm
9
A parallel beam of light in air makes an angle of 47.5\(^\circ \) with the surface of a glass plate having a refractive index of 1.66. What is the angle between the reflected part of the beam and the surface of the glass?
  • A
    43.5\(^\circ \)
  • B
    41.5\(^\circ \)
  • C
    47.5\(^\circ \)
    Correct
  • D
    45.5\(^\circ \)
10
A parallel beam of light in air makes an angle of 47.5\(^\circ \) with the surface of a glass plate having a refractive index of 1.66. What is the angle between the refracted beam and the surface of the glass?
  • A
    67.0\(^\circ \)
  • B
    66.0\(^\circ \)
    Correct
  • C
    69.0\(^\circ \)
  • D
    68.0\(^\circ \)
11
Light traveling in air is incident on the surface of a block of plastic at an angle of 62.7\(^\circ \) to the normal and is bent so that it makes a 48.1\(^\circ \) angle with the normal in the plastic. Find the speed of light in the plastic
  • A
    2.51 \( \times {\rm{ 1}}{0^{\rm{8}}}{\rm{m }}{{\rm{s}}^{-{\rm{1}}}}\)
    Correct
  • B
    2.81 \( \times {\rm{ 1}}{0^{\rm{8}}}{\rm{m }}{{\rm{s}}^{-{\rm{1}}}}\)
  • C
    2.61 \( \times {\rm{ 1}}{0^{\rm{8}}}{\rm{m }}{{\rm{s}}^{-{\rm{1}}}}\)
  • D
    2.71 \( \times {\rm{ 1}}{0^{\rm{8}}}{\rm{m }}{{\rm{s}}^{-{\rm{1}}}}\)
12
The critical angle for total internal reflection at a liquid–air interface is 42.5\(^\circ \) If a ray of light traveling in the liquid has an angle of incidence at the interface of 35\(^\circ \) what angle does the refracted ray in the air make with the normal?
  • A
    60.1\(^\circ \)
  • B
    59.1\(^\circ \)
  • C
    58.1\(^\circ \)
    Correct
  • D
    61.1\(^\circ \)
13
The critical angle for total internal reflection at a liquid–air interface is 42.5\(^\circ \) If a ray of light traveling in air has an angle of incidence at the interface of 35\(^\circ \) what angle does the refracted ray in the liquid make with the normal?
  • A
    23.8\(^\circ \)
  • B
    24.8\(^\circ \)
  • C
    22.8\(^\circ \)
    Correct
  • D
    25.8\(^\circ \)
14
Unpolarized light with intensity I0 is incident on two polarizing filters. The axis of the first filter makes an angle of 60.0\(^\circ \) with the vertical, and the axis of the second filter is horizontal. What is the intensity of the light after it has passed through the second filter
  • A
    0.475 \({{\rm{I}}_0}\)
  • B
    0.675 \({{\rm{I}}_0}\)
  • C
    0.575 \({{\rm{I}}_0}\)
  • D
    0.375 \({{\rm{I}}_0}\)
    Correct
15
A parallel beam of unpolarized light in air is incident at an angle of 54.5\({{\rm{I}}_0}\) (with respect to the normal) on a plane glass surface.The reflected beam is completely linearly polarized. What is the refractive index of the glass?
  • A
    1.4
    Correct
  • B
    1.42
  • C
    1.46
  • D
    1.44