JEE Questions for Physics Wave Optics Quiz 1 - MCQExams.com

A thin film of soap solution (n =1.lies on the top of a glass plate (n = 1.5). When visible light is incident almost normal to the plate, two adjacent reflection maxima are observed at two wavelengths 400 and 630 nm. The minimum thickness of the soap solution is
  • 420 nm
  • 450 nm
  • 630 nm
  • 1260 nm
Which phenomenon best supports the theory that matter has a wave nature?
  • Electron momentum
  • Electron diffraction
  • Photon momentum
  • Photon diffraction
Which one of the following phenomenon exhibits particle's nature of light ?
  • Interference
  • Diffraction
  • Polarisation
  • Photoelectric effect
Two coherent monochromatic beams of intensities I and 4I respectively are superposed. The maximum and minimum intensities in the resulting pattern are
  • 5I and 3I
  • 9I and 3I
  • 4I and I
  • 9I and I
A Young's double slit set up for interference is shifted from air to within water, then the fringe width
  • becomes infinite
  • decreases
  • increases
  • remain unchanged
Interference may be seen using two independent
  • sodium lamps
  • fluorescent tubes
  • lasers
  • mercury vapour lamps
A very thin film that reflects white light appears.
  • coloured
  • white
  • black
  • red
In Young's double slit experiment, the slit width and the distance of slits from the screen both are doubled. The fringe width
  • increases
  • decreases
  • remains unchanged
  • None of these
Resolving power of a telescope will be more, if the diameter a of the objective is
  • larger
  • smaller
  • resolving power does not depend on a
  • None of the above
An optically active compound
  • rotates the plane polarised light
  • changing the direction of polarised light
  • do not allow plane polarised light to pass through
  • None of these
The diagram below shows, two sources A and B, vibrating in phase, in the same uniform medium and producing circular wave fronts. Which phenomenon occurs at point P?
Physics-Wave Optics-95277.png
  • Destructive interference
  • Constructive interference
  • Reflection
  • Refraction
In a given direction, the intensities of the scattered light by a scattering substance for two beams of light are in the ratio of 256: 81. The ratio of the frequency of the first beam to the frequency of the second beam is
  • 64 : 127
  • 1 : 2
  • 64 : 27
  • None of these
According to Newton's corpuscular theory, the speed of light is
  • same in all the medium
  • lesser in rarer medium
  • lesser in denser medium
  • independent of the medium
Which one of the following property of light does not support wave theory of light?
  • Light obeys laws of reflection and refraction
  • Light waves get polarised
  • Light shows photoelectric effect
  • Light shows interference
In Huygen's wave theory, the locus of all points in the same state of vibration is called
  • a half period zone
  • oscillator
  • a wave front
  • a ray
The wavefront of distant source of unknown shape is approximately
  • elliptical
  • spherical
  • cylindrical
  • plane
Which of the following generates a plane wavefront?
  • α – rays
  • β – rays
  • γ – rays
  • None of these
The wave theory of light, in its original form, was first proposed by
  • Issac Newton
  • Christian Huygen's
  • Thomas Young
  • Augustin Jean Fresnel
Which of the following cannot be explained on the basis of wave nature of light?
I. Polarisation
II. Optical activity
III. Photoelectric effect
1V. Compton effect
  • III and IV
  • II and III
  • I and III
  • II and IV
Select the right option in the following
  • Christian Huygens, a contemporary of Newton established the wave theory of light by assuming that light waves were transverse
  • Maxwell provided the theoretical evidence that light is transverse wave
  • Thomas Young experimentally proved the wave behaviour of light and Huygen's assumption
  • All the statements given above, correctly answers the question what is light?
A is an essential condition for coherent sources. Here, A refers to
  • constant phase difference
  • equal amplitude
  • Both (a) and (b) are correct
  • Both (a) and (b) are incorrect
In a double slit interference experiment, the fringe width obtained with a light of wavelength 5900 Å was 1.2 mm for parallel narrow slits placed 2 mm apart. In this arrangement, if the slit separation is increased by one-and-half times the previous value, then the fringe width is
  • 0.9 mm
  • 0.8 mm
  • 1.8 mm
  • 1.6 mm
Two sources are said to be coherent if they produce waves
  • having a constant phase difference
  • of equal wavelength
  • of equal speed
  • having same shape of wavefront
If Young's double slit experiment is performed in water
  • the fringe width will decrease
  • the fringe width will increase
  • the fringe width will remain unchanged
  • there will be no fringe
For sustained interference fringes in double slit experiment, essential conditions is/are
I. sources must be coherent
II. the intensities of the two sources must be equal
Here, the correct option/s/is/are
  • Neither I nor II
  • Both I and II
  • only I
  • only II
If Young's double slit experiment, is performed in water
  • the fringe width will decrease
  • the fringe width will increase
  • the fringe width will remain unchanged
  • there will be no fringe
In Young's double slit experiment if the slits widths are in the ratio 1 : 9, the ratio of the intensities at minima to that at maxima will be
  • 1
  • 1/9
  • 1/4
  • 1/3
In a Young's double slit experiment, the fringe width is found to be 2 mm, when light of wavelength 6000 A° is used. Find the change in fringe width if the whole apparatus is immersed in water of refractive index 1.33.
  • 0.5 mm
  • 1 mm
  • 1.5 mm
  • 2 mm
What is the minimum thickness of a thin film required for constructive interference in the reflected light from it? Given, the refractive index of the film = 1.5, wavelength of the light incident on the film = 600 nm.
  • 100 nm
  • 300 nm
  • 50 nm
  • 200 nm
A narrow slit of width 2mm is illuminated by monochromatic light of wavelength 500 nm. The distance between the first minima on either side on a screen at a distance of 1 m is
  • 5 mm
  • 0.5 mm
  • 1 mm
  • 10 mm
  • 2.5 mm
When two coherent monochromatic beams of intensity I and 9I interfere, the possible maximum and minimum intensities of the resulting beam are
  • 9I and I
  • 9I and 4 I
  • 16 I and 4I
  • 16I and I
100π phase difference = ... path difference.
  • 10λ
  • 25λ
  • 50λ
  • 100λ
Two coherent sources of different intensities send waves which interfere. The ratio of maximum intensity to the minimum intensity is 25. The intensities of the sources are in the ratio
  • 25 : 1
  • 5 : 1
  • 9 : 4
  • 25 : 16
Two beams of light will not give rise to an interference pattern, if
  • they are coherent
  • they have the same wavelength
  • they are linearly polarised perpendicular to each other
  • they are not monochromatic
If fringe width is 0 4 mm, the distance between fifth bright and third dark band on same side is
  • 1 mm
  • 2 mm
  • 3 mm
  • 4 mm
In an interference experiment, third bright fringe is obtained at a point on the screen with a light of 700 nm. What should be the wavelength of the light source in order to obtain 5th bright fringe at the same point?
  • 500 nm
  • 630 nm
  • 750 nm
  • 420 nm
For the constructive interference the path difference between the two interfering waves must be equal to
  • (2n +π
  • 2nπ
  • nλ
  • (2n +λ/2
In Young's double slit experiment, a third slit is made in between the double slits. Then,
  • intensity of fringes totally disappears
  • only bright light is observed on the screen
  • fringes of unequal width are formed
  • contrast between bright and dark fringes is reduced
Light of wavelength 6000 Å falls on a single slit of width 0.1 mm. The second minimum will be formed for the angle of diffraction of
  • 0.08 rad
  • 0.06 rad
  • 0.12 rad
  • 0.15 rad
  • 0.012 rad
In a Young's double slit experiment, constructive interference is produced at a certain point P. The intensities of light at P due to the individual sources are 4 and 9 units. The resultant intensity at point P will be
  • 13 units
  • 25 units
  • √97 units
  • 5 units
In a Young's double slit experiment, I1 / I2 = 16/9. Ratio of maximum to minimum intensity is
  • 1 : 49
  • 9 : 16
  • 16 : 9
  • 49 : 1
In an interference experiment, the spacing between successive maxima or minima is
  • λd / D
  • λD / d
  • dD / λ
  • λd / 4D
In Young's double slit experiment, slit separation is 0.6 mm and the separation between slit and screen is 1.2 m. The angular width is (the wavelength of light used is 4800A°).
  • 30 rad
  • 8 × 10-4 rad
  • 12 rad
  • 70.5 rad
Colours in thin films are due to
  • diffraction phenomenon
  • scattering phenomenon
  • interference phenomenon
  • polarisation phenomenon
In a double slit experiment, the distance between slits is increased 10 times whereas, their distance from screen is halved, then what is the fringe width?
  • It remains same
  • Becomes 1/10
  • Becomes 1/20
  • Becomes 1/90
To demonstrate the phenomenon of interference we require two sources, which emits radiations of
  • nearly the same frequency
  • the same frequency
  • different wavelength
  • the same frequency and having a definite phase relationship
On introducing a thin film in the path of one of the two interfering beams, the central fringe will shift by one fringe width. If μ =1.5, the thickness of the film is (wavelength of monochromatic light is λ)
  • 4λ
  • 3λ
  • 2λ
  • λ
The maximum number of possible interference maxima for slit separation equal to twice the wavelength is Young's double-slit experiment, is
  • infinite
  • five
  • three
  • zero
The ratio of maximum and minimum intensities of two sources is 4 : 1. The ratio of their amplitudes is
  • 1 : 3
  • 3 : 1
  • 1 : 9
  • 1 : 16
A beam of light of wavelength 600 nm from a distant source falls on a single slit 1 mm wide and the resulting diffraction pattern is observed on a screen 2 m away. The distance between the first dark fringes on either side of the central bright fringe is
  • 1.2 cm
  • 1.2 mm
  • 2.4 cm
  • 2.4 mm
0:0:1


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