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Resolving power of telescope can be increased by increasing
1. the wavelengt
2. the diameter of objective
3. the diameter of eyepiece
4. the focal length of eyepiece
Wave Optics MCQ Question 2. Polarisation of light proves
1. corpuscular nature of light.
2. quantum nature of light.
3. transverse wave nature of light.
4. longitudinal wave nature of light.
The wavefront due to a source situated at infinity is
1. spherical
2. cylindrical
3. planar
4. circular
A laser beam is coherent because it contains
1. waves of several wavelengths.
2. incoherent waves of a single wavelength.
3. coherent waves of several wavelengths
4. coherent waves of a single wavelength.
According to Huygens’ principle, light is a form of
1. particle
2. rays
3. wave
4. radiation
Two coherent monochromatic light beams of intensities I and 41 superimpose. The maximum and minimum possible intensities in the resulting beam are:
1. 5I and I
2. 5I and 3I
3. 3I and i
4. 9I and I
When exposed to sunlight, thin films of oil on water of ten exhibit brilliant colours due to the phenomenon of
1. interference
2. diffraction
3. dispersion
4. polarisation
When compact disk is illuminated by a source of white light, coloured lines are observed. This is due to
1. dispersion
2. diffraction
3. interference
4. refraction
Resolving power of microscope depends upon
1. wavelength of light used (directly proportional)
2. wavelength of light used (inversely proportional)
3. frequency of light used
4. focal length of objective
A double slit interference experiment is carried out in air and the entire arrangement is dipped in water. The fringe width
1. increases
2. decreases
3. remains unchanged.
4. fringe pattern disappears.
The idea of secondary wavelets for the. propagation of a wave was first given by
1. Newton
2. Huygens
3. Maxwell
4. Fresnel
Light propagates rectilinearly, due to
1. wave nature
2. wavelengt
3. velocity
4. frequency
The refractive index of glass is 1.5 for light waves of X = 6000 A in vacuum. Its wavelength in glass is
1. 2000 Å
2. 4000 Å
3. 1000 Å
4. 3000 Å
The phenomena which is not explained by Huygen’s construction of wavefront
1. reflection
2. diffraction
3. refraction
4. origin of spectra
Two slits in Young’s double slit experiment have widths in the ratio 81 :1. The ratio of the amplitudes of light waves is
1. 3:1
2. 3:2
3. 9:1
4. 6:1
The angular resolution of a 10 cm diameter telescope at a wavelength of 5000 A is of the order of
1. 106 rad
2. 10-2 rad
3. 10-4 rad
4. 10-6 rad
The velocity of light in air is 3 * 108 ms-1 and that in water is 2.2 * 108 ms” . The polarising angle of incidence is
1. 45°
2. 50°
3. 53.74°
4. 63
Consider the diffraction pattern for a small pinhole. As the size of the hole is increased
1. the size decreases.
2. the intensity decreases.
3. the size increases.
4. the intensity decreases.
For light diverging from a point source
1. the wavefront is spherical.
2. the intensity increases in proportion to the distance squared.
3. the wavefront is parabolic.
4. the intensity at the wavefront does not depend on the distance.
Consider sunlight incident on a slit of width 104 A. The image seen through the slit shall
1. be a fine sharp slit white in colour at the centre.
2. a bright slit white at the centre diffusing to zero intensities at the edges.
3. a bright slit white at the centre diffusing to regions of different colours.
4. only be a diffused slit white in colour
The phenomenon of interference is based on
1. conservation of momentum.
2. conservation of energy.
3. conservation of momentum and energy.
4. quantum nature of light.
In Young’s double slit experiment, if the monochromatic source of yellow light is replaced by red light, the fringe width
1. increase
2. decrease
3. remains constant
4. none of these
A short pulse of white light is incident from air to a glass slab at normal incidence. After travelling through the slab, the first colour to emerge is
1. yellow
2. blue
3. green
4. red

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