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
Is light a particle or a wave?
  • A
    Light is a set of waves
  • B
    Light is schizophrenic i.e. sometimes it behaves like a particle and other times like a wave.
  • C
    Light is a set of particles
  • D
    Both particle and wave approaches help us understand different phenomenon
    Correct
2
The propagation of light is best described by,
  • A
    particle model
  • B
    a wave model
    Correct
  • C
    None of the above
  • D
    dual / schizophrenic model
3
Emission and absorption is best described by,
  • A
    particle model
    Correct
  • B
    a wave model
  • C
    None of the above
  • D
    dual / schizophrenic model
4
wave front is
  • A
    locus of all adjacent points at which the phase of vibration of a physical quantity associated with the wave is the same
    Correct
  • B
    locus of all adjacent points at which the Electric field is the same
  • C
    series of points on the wave with same amplitude
  • D
    series of points on the wave with same frequency
5
A ray is an imaginary
  • A
    line from source to horizon
  • B
    line along the direction perpendicular to travel of the wave
  • C
    line along the direction at an angle to the travel of the wave
  • D
    line along the direction of travel of the wave
    Correct
6
According to Huygens principle
  • A
    each point on a wave front is a source of secondary waves
    Correct
  • B
    No point on a wave front is a source of secondary waves
  • C
    None of the above
  • D
    each point on a wave front is a sink of secondary waves
7
According to Huygens construction relation between old and new wave fronts is
  • A
    new wave front is parallel to old wave front
  • B
    new wave front is perpendicular to old wave front
  • C
    new wave front is tangential to old wave front
  • D
    new wave front is the forward envelope of the secondary waves
    Correct
8
Relation between ray and wave front is
  • A
    Rays are tangential to wave front
  • B
    Rays are parallel to wave front
  • C
    Rays are perpendicular to wave front
    Correct
  • D
    Rays are at acute angle to wave front
9
Approximate Doppler shift formula for light is
  • A
    \({{\Delta \upsilon } \over \upsilon } = {{{v_{rad}}} \over c}\)
  • B
    \({{\Delta \upsilon } \over \upsilon } = - {{{v_{rad}}} \over c}\)
    Correct
  • C
    \({{\Delta \upsilon } \over \upsilon } = - {{{v_{rad}}} \over {2c}}\)
  • D
    \({{\Delta \upsilon } \over \upsilon } = 2{{{v_{rad}}} \over c}\)
10
According to superposition principle in relation to displacements produced by a number of waves
  • A
    resultant displacement is the vector sum of the displacements produced
    Correct
  • B
    resultant displacement is the dot product of the displacements produced
  • C
    resultant displacement is the scalar sum of the displacements produced
  • D
    resultant displacement is the arithmetic sum of the displacements produced
11
Two sources of light are coherent if they have
  • A
    different frequency and random phases
  • B
    same frequency and with a constant phase relationship
    Correct
  • C
    same frequency and change phase randomly
  • D
    different frequency and with a constant phase relationship
12
Interference effects of light from two sources can be observed if
  • A
    the sources are of different frequency
  • B
    the sources are independent
  • C
    the sources are different frequency and random phases
  • D
    the sources are coherent
    Correct
13
If we have two coherent sources \({{\rm{S}}_{\rm{1}}}{\rm{and }}{{\rm{S}}_{\rm{2}}}\) vibrating in phase, then for an arbitrary point P constructive interference is observed whenever the path difference is
  • A
    An even multiple of wavelength
  • B
    A fraction of a wavelength
  • C
    An odd multiple of wavelength
  • D
    An integral multiple of wavelength
    Correct
14
If we have two coherent sources \({{\rm{S}}_{\rm{1}}}{\rm{and }}{{\rm{S}}_{\rm{2}}}\) vibrating in phase, then for an arbitrary point P destructive interference is observed whenever the path difference is
  • A
    \(n\lambda where{\rm{ }}n = 0,1,2,3 \ldots \)
  • B
    \((n + {1 \over 2})\lambda where{\rm{ }}n = 0,1,2,3 \ldots \)
    Correct
  • C
    \((n + {1 \over {2}})\lambda where {\rm{ }}n = 0,3,5 \ldots \)
  • D
    \((n + {1 \over {3}})\lambda where{\rm{ }}n = 0,1,2,3 \ldots \)
15
If we have two coherent sources \({{\rm{S}}_{\rm{1}}}{\rm{and }}{{\rm{S}}_{\rm{2}}}\) vibrating in phase with same amplitude, then for an arbitrary point P with path difference corresponding to \(\phi \) , the resultant intensity if the intensity due to each is I0 would be
  • A
    \({I_0}co{s^2}\left( \emptyset \right)\)
  • B
    \(4{I_0}co{s^2}\left( {\emptyset /2} \right)\)
    Correct
  • C
    \({I_0}co{s^2}\left( {\emptyset /2} \right)\)
  • D
    \(4{I_0}co{s^2}\left( \emptyset \right)\)