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KCET SERIES
Physics

Wave Optics

43 previous year questions.

Volume: 43 Ques
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Chapter Questions
43 MCQs

01
PYQ 1996
medium
physics ID: kcet-199
Unpolarised light converts to partially or plane polarised light by many processes, Which of the following does not do that ?
1
reflection
2
diffraction
3
double refraction
4
scattering
02
PYQ 1997
medium
physics ID: kcet-199
A beam of light is passed through a polaroid and the latter is rotated with the beam of light as axis. The intensity of the emergent light varies between a maximum and minimum. Then the light used is
1
a mixture of elliptically polarised and unpolarised light only
2
elliptically polarised light only
3
Either (1) or (2)
4
Neither (1) nor (2).
03
PYQ 1997
medium
physics ID: kcet-199
Optically active substance among the following is
1
calcite
2
tourmaline
3
quartz
4
sodium chloride.
04
PYQ 1998
medium
physics ID: kcet-199
Bright colours exhibited by spider's web, exposed to sun light are due to
1
interference
2
resolution
3
diffraction
4
polarisation
05
PYQ 1998
medium
physics ID: kcet-199
Light of certain wavelength and intensity ejects photoelectrons from a metal plate. Then this beam is replaced by another beam of smaller wavelength and smaller intensity. As a result
1
kinetic energy of the photoelectrons decreases but the strength of the photoelectric current increases
2
kinetic energy of the photoelectrons increases but the strength of the photoelectric current decreases
3
no change occurs
4
emission of photoelectrons stops.
06
PYQ 1998
medium
physics ID: kcet-199
Velocity of light, according to this theory, is greater in a denser medium than in a rarer medium
1
Electromagnetic theory
2
Quantum theory
3
Corpuscular theory
4
Wave theory
07
PYQ 1998
medium
physics ID: kcet-199
Numerical aperture of an oil immersion objective using oil of R.I. 1.5 is 0.75. Then, its numerical aperture, when kept in air is
1
0.25
2
0.5
3
1
4
0.3
08
PYQ 1998
medium
physics ID: kcet-199
A mirror produces a magnified erect image of an object. The nature of the mirror is
1
concave
2
plane
3
convex
4
neither convex nor cancave
09
PYQ 1998
medium
physics ID: kcet-199
Time of exposure for a photographic print is 10 s, when a lamp of 50 cd is placed at 1 m from it. Then another lamp of luminous intensity I is used, and is kept at 2 m from it. If the time of exposure now is 20 sec, the value of I is (cd)
1
200
2
20
3
100
4
25
10
PYQ 1999
medium
physics ID: kcet-199
A mirror forms a real image of unit magnification. Its nature is
1
concave
2
plane
3
conve
4
neither convex nor concave
11
PYQ 1999
medium
physics ID: kcet-199
Biaxial crystal among the following is
1
mica
2
tourmaline
3
calcite
4
quartz
12
PYQ 1999
medium
physics ID: kcet-199
Biaxial crystal among the following is
1
selenite
2
tourmaline
3
calcite
4
quartz.
13
PYQ 1999
medium
physics ID: kcet-199
When a thin metal plate is placed in the path of one of the interfering beams of light
1
the fringes become brighter
2
the fringes disappear
3
the fringe width increases
4
the fringe becomes blurred.
14
PYQ 2000
medium
physics ID: kcet-200
In Young's double slit experiment the separation between the slits is halved and the distance between the slits and the screen is doubled. The fringe width will
1
be quadrupled
2
be doubled
3
be halved
4
remain the same.
15
PYQ 2000
medium
physics ID: kcet-200
The phenomenon of diffraction of light was discovered by
1
Fresnel
2
Grimaldi
3
Huygens
4
Newton
16
PYQ 2000
medium
physics ID: kcet-200
In a cinema hall the distance between the projector and the screen is increased by 2 %. Now the intensity of illumination of the screen
1
decreases by 4%
2
increases by 2%
3
decreases by 2%
4
increases by 4%
17
PYQ 2001
medium
physics ID: kcet-200
A length of a certain solution causes right-handed rotation of . A length of another solution causes left-handed rotation of . The optical rotation caused by length of a mixture of the above solutions in the volume ratio is
1
right handed rotation of
2
left handed rotation of
3
right handed rotation of
4
left handed rotation of
18
PYQ 2001
medium
physics ID: kcet-200
If white light is used in Young's double-slit experiment,
1
very few coloured fringes can be seen, with first order violet fringes being closer to the central white fringe
2
very few coloured fringes can be seen with first order red fringes being closer to the central white fringe.
3
a very large number of coloured fringes can be seen
4
a very large number of coloured fringes with a central white fringe can be seen.
19
PYQ 2001
medium
physics ID: kcet-200
In the experiment of diffraction at a single slit, if the slit width is decreased, the width of the central maximum
1
decreases in both Fresnel and Fraunhoffer diffraction
2
increases in both Fresnel and Fraunhoffer diffraction
3
decreases in Fresnel diffraction but increases in Fraunhoffer diffraction
4
increases in Fresnel diffraction but decreases in Fraunhoffer diffraction
20
PYQ 2002
easy
physics ID: kcet-200
When one of the slits of Young's experiment is covered with a transparent sheet of thickness 4.8 mm, the central fringe shifts to a position originally occupied by the 30th bright fringe. What should be the thickness of the sheet if the central fringe has to shift to the position occupied by 20th bright fringe ?
21
PYQ 2002
medium
physics ID: kcet-200
In Young's double slit experiment, the central bright fringe can be identified
1
by using white light instead of monochromatic light
2
as it is narrower than other bright fringes
3
as it is wider than other bright fringes
4
as it has a greater intensity than the other bright fringes.
22
PYQ 2003
medium
physics ID: kcet-200
As a result of interference of two coherent sources of light, energy is
1
redistributed and distribution changes with time
2
decreased
3
redistributed and distribution does not vary with time
4
increased
23
PYQ 2003
medium
physics ID: kcet-200
Yellow light is used in single slit diffraction experiment with slit width 0.6 mm. If yellow light is replaced by X-ray then the pattern reveals
1
less number of fringes
2
more number of fringes
3
no diffraction pattern
4
that the central maximum becomes narrower.
24
PYQ 2003
medium
physics ID: kcet-200
The phenomenon of rotation of plane polarised light is called
1
optical activity
2
dichroism
3
rear effect
4
double refraction
25
PYQ 2004
medium
physics ID: kcet-200
A beam of light of wavelength from a distant source falls on a single slit wide and the resulting diffraction pattern is observed on a screen away. The distance between the first dark fringes on either side of the central bright fringe is
1
1.2 cm
2
1.2 mm
3
2.4 cm
4
2.4 mm
26
PYQ 2007
medium
physics ID: kcet-200
A single slit Fraunhoffer 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
2
3
4
27
PYQ 2007
medium
physics ID: kcet-200
In Young?? double slit experiment with sodium vapour lamp of wavelength 589 nm and the slits 0.589 mm apart, the half angular width of the central maximum is
1
2
3
4
28
PYQ 2007
medium
physics ID: kcet-200
Light from two coherent sources of the same amplitude and wavelength illuminates the screen. The intensity of the central maximum is . If the sources were incoherent, the intensity at the same point will be
1
2
3
4
29
PYQ 2007
medium
physics ID: kcet-200
The head lights of a jeep are apart. If the pupil of the eye of an observer has a diameter of and light of wavelength is used, what should be the maximum distance of the jeep from the observer if the two head lights are just separated?
1
33.9 km
2
33.9 m
3
3.34 m
4
3.39 m
30
PYQ 2007
medium
physics ID: kcet-200
When the angle of incidence is on the surface of a glass slab, it is found that the reflected ray is completely polarised. The velocity of light in glass is
1
2
3
4
31
PYQ 2009
medium
physics ID: kcet-200
Two luminous point sources separated by a certain distance are at from an observer. If the aperture of his eye is and the wavelength of light used is , the distance of separation between the point sources are just seen to be resolved is
1
24.4 m
2
2.44 m
3
1.22 m
4
12.2 m
32
PYQ 2010
medium
physics ID: kcet-201
Critical angle for certain medium is . The polarizing angle of that medium is .......
1
2
3
4
33
PYQ 2011
medium
physics ID: kcet-201
Wavefront is the locus of all points, where the particles of the medium vibrate with the same
1
phase
2
amplitude
3
frequency
4
period
34
PYQ 2011
medium
physics ID: kcet-201
A parallel beam of light of wavelength gets diffracted by a single slit of width . The angular position of the first minima of diffracted light is
1
rad
2
rad
3
rad
4
rad
35
PYQ 2011
medium
physics ID: kcet-201
Consider the following statements in case of Young's double slit experiment. a) A slit is necessary if we use an ordinary extended source of light. b) A slit is not needed if we use an ordinary but well collimated beam of light. c) A slit is not needed if we use a spatially coherent source of light. Which of the above statements are correct?
1
(a), (b) and (c)
2
(b) and ( c)
3
(b) and (c)
4
(a) and (c)
36
PYQ 2012
medium
physics ID: kcet-201
In single slit experiment, the width of the slit is reduced. Then, the linear width of the principal maxima
1
increases but becomes less bright
2
decreases but becomes more bright
3
increases but becomes more bright
4
decreases but becomes less bright
37
PYQ 2012
medium
physics ID: kcet-201
For sustained interference fringes in double slit experiment, essential condition/s is/are (1) sources must be coherent (2) the intensities of the two sources must be equal Here, the correct option/s is/are
1
Neither (1) nor (2)
2
Both (1) and (2)
3
only (1)
4
only (2)
38
PYQ 2012
medium
physics ID: kcet-201
In Young's double slit experiment, fringes of width are produced on a screen kept at a distance of 1 m from the slit. When the screen is moved away by m, fringe width changes by m. The separation between the slits is . The wavelength of the light used is
1
500 nm
2
600 nm
3
700 nm
4
400 nm
39
PYQ 2017
easy
physics ID: kcet-201
According to Huygen's principle, during refraction of light from air to a denser medium
1
Wavelength and speed decrease
2
Wavelength and speed increase
3
Wavelength increases but speed decreases
4
Wavelength decreases but speed increases
40
PYQ 2018
medium
physics ID: kcet-201
In a Fraunhofer diffraction at a single slit, if yellow light illuminating the slit is replaced by blue light, then diffraction bands
1
Remain unchanged
2
Become wider
3
Disappear
4
Become narrower
41
PYQ 2019
medium
physics ID: kcet-201
Due to Doppler?? effect the shift in wavelength observed is 0.1 ? for a star producing wavelength 6000 ?. Velocity of recession of the star will be
1
5 km/s
2
25 km/s
3
20 km/s
4
10 km/s
42
PYQ 2022
easy
physics ID: kcet-202

In case of Fraunhofer diffraction on a single slit the diffraction pattern on the screen correct for which of the following statements ?

1

Central dark band having uniform brightness on either side.

2

Central dark band having alternate dark and bright bands of decreasing intensity on either side.

3

Central bride band having dark bands on either sides.

4

Central bride band having alternate dark and bright bands of decreasing intensity on either side.

43
PYQ 2024
medium
physics ID: kcet-202
A motor-cyclist moving towards a huge cliff with a speed of 18 km/h, blows a horn of source frequency 325 Hz. If the speed of the sound in air is 330 m/s, the number of beats heard by him is
1
5
2
4
3
7
4
6