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question_answer1)
A polariser is used to [CPMT 1999]
A)
Reduce intensity of light done
clear
B)
Produce polarised light done
clear
C)
Increase intensity of light done
clear
D)
Produce unpolarised light done
clear
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question_answer2)
Light waves can be polarised as they are [CBSE PMT 1993; KCET 1994; AFMC 1997; J & K CET 2002; CPMT 2005]
A)
Transverse done
clear
B)
Of high frequency done
clear
C)
Longitudinal done
clear
D)
Reflected done
clear
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question_answer3)
Through which character we can distinguish the light waves from sound waves [CBSE PMT 1990; RPET 2000, 02]
A)
Interference done
clear
B)
Refraction done
clear
C)
Polarisation done
clear
D)
Reflection done
clear
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question_answer4)
The angle of polarization for any medium is 60o, what will be critical angle for this [UPSEAT 1999]
A)
\[{{\sin }^{-1}}\sqrt{3}\] done
clear
B)
\[{{\tan }^{-1}}\sqrt{3}\] done
clear
C)
\[{{\cos }^{-1}}\sqrt{3}\] done
clear
D)
\[{{\sin }^{-1}}\frac{1}{\sqrt{3}}\] done
clear
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question_answer5)
The angle of incidence at which reflected light is totally polarized for reflection from air to glass (refraction index n) is [AIEEE 2004; UPSEAT 2005]
A)
\[{{\sin }^{-1}}(n)\] done
clear
B)
\[{{\sin }^{-1}}\left( \frac{1}{n} \right)\] done
clear
C)
\[{{\tan }^{-1}}\left( \frac{1}{n} \right)\] done
clear
D)
\[{{\tan }^{-1}}(n)\] done
clear
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question_answer6)
Which of following cannot be polarised [Kerala PMT 2001]
A)
Radio waves done
clear
B)
Ultraviolet rays done
clear
C)
Infrared rays done
clear
D)
Ultrasonic waves done
clear
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question_answer7)
A polaroid is placed at 45o to an incoming light of intensity \[{{I}_{0}}\]. Now the intensity of light passing through polaroid after polarization would be [CPMT 1995]
A)
\[{{I}_{0}}\] done
clear
B)
\[{{I}_{0}}/2\] done
clear
C)
\[{{I}_{0}}/4\] done
clear
D)
Zero done
clear
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question_answer8)
Plane polarized light is passed through a polaroid. On viewing through the polaroid we find that when the polaroid is given one complete rotation about the direction of the light, one of the following is observed [MNR 1993]
A)
The intensity of light gradually decreases to zero and remains at zero done
clear
B)
The intensity of light gradually increases to a maximum and remains at maximum done
clear
C)
There is no change in intensity done
clear
D)
The intensity of light is twice maximum and twice zero done
clear
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question_answer9)
Out of the following statements which is not correct [CPMT 1991]
A)
When unpolarised light passes through a Nicol's prism, the emergent light is elliptically polarized done
clear
B)
Nicol's prism works on the principle of double refraction and total internal reflection done
clear
C)
Nicol's prism can be used to produce and analyze polarized light done
clear
D)
Calcite and Quartz are both doubly refracting crystals done
clear
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question_answer10)
A ray of light is incident on the surface of a glass plate at an angle of incidence equal to Brewster's angle \[\varphi \]. If \[\mu \] represents the refractive index of glass with respect to air, then the angle between reflected and refracted rays is [CPMT 1989]
A)
\[90+\varphi \] done
clear
B)
\[{{\sin }^{-1}}(\mu \cos \varphi )\] done
clear
C)
90o done
clear
D)
\[{{90}^{o}}-{{\sin }^{-1}}(\sin \varphi /\mu )\] done
clear
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question_answer11)
Figure represents a glass plate placed vertically on a horizontal table with a beam of unpolarised light falling on its surface at the polarising angle of 57o with the normal. The electric vector in the reflected light on screen S will vibrate with respect to the plane of incidence in a [CPMT 1988]
A)
Vertical plane done
clear
B)
Horizontal plane done
clear
C)
Plane making an angle of 45o with the vertical done
clear
D)
Plane making an angle of 57o with the horizontal done
clear
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question_answer12)
A beam of light AO is incident on a glass slab \[(\mu =1.54)\] in a direction as shown in figure. The reflected ray OB is passed through a Nicol prism on viewing through a Nicole prism, we find on rotating the prism that [CPMT 1986]
A)
The intensity is reduced down to zero and remains zero done
clear
B)
The intensity reduces down somewhat and rises again done
clear
C)
There is no change in intensity done
clear
D)
The intensity gradually reduces to zero and then again increases done
clear
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question_answer13)
Polarised glass is used in sun glasses because [CPMT 1981]
A)
It reduces the light intensity to half an account of polarisation done
clear
B)
It is fashionable done
clear
C)
It has good colour done
clear
D)
It is cheaper done
clear
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question_answer14)
In the propagation of electromagnetic waves the angle between the direction of propagation and plane of polarisation is [CPMT 1978]
A)
0o done
clear
B)
45o done
clear
C)
90o done
clear
D)
180o done
clear
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question_answer15)
The transverse nature of light is shown by [CPMT 1972, 74, 78; RPMT 1999; AFMC 2001; AIEEE 2002; MP PET 2004; MP PMT 2000, 04; UPSEAT 2005]
A)
Interference of light done
clear
B)
Refraction of light done
clear
C)
Polarisation of light done
clear
D)
Dispersion of light done
clear
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question_answer16)
A calcite crystal is placed over a dot on a piece of paper and rotated, on seeing through the calcite one will be see [CPMT 1971]
A)
One dot done
clear
B)
Two stationary dots done
clear
C)
Two rotating dots done
clear
D)
One dot rotating about the other done
clear
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question_answer17)
A light has amplitude A and angle between analyser and polariser is 60°. Light is reflected by analyser has amplitude [UPSEAT 2001]
A)
\[A\sqrt{2}\] done
clear
B)
\[A/\sqrt{2}\] done
clear
C)
\[\sqrt{3}A/2\] done
clear
D)
\[A/2\] done
clear
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question_answer18)
When light is incident on a doubly refracting crystal, two refracted rays-ordinary ray (O-ray) and extra ordinary ray (E-ray) are produced. Then [KCET 2001]
A)
Both O-ray and E-ray are polarised perpendicular to the plane of incidence done
clear
B)
Both O-ray and E-ray are polarised in the plane of incidence done
clear
C)
E-ray is polarised perpendicular to the plane of incidence and O-ray in the plane of incidence done
clear
D)
E-ray is polarised in the plane of incidence and O-ray perpendicular to the plane of incidence done
clear
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question_answer19)
Light passes successively through two polarimeters tubes each of length 0.29m. The first tube contains dextro rotatory solution of concentration 60kgm?3 and specific rotation 0.01rad m222222222222222222222kg?1. The second tube contains laevo rotatory solution of concentration 30kg/m3 and specific rotation 0.02 radm2kg?1. The net rotation produced is [KCET 2002]
A)
15° done
clear
B)
0° done
clear
C)
20° done
clear
D)
10° done
clear
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question_answer20)
\[{{V}_{o}}\]and \[{{V}_{E}}\]represent the velocities,\[{{\mu }_{o}}\]and\[{{\mu }_{E}}\]the refractive indices of ordinary and extraordinary rays for a doubly refracting crystal. Then [KCET 2002]
A)
\[{{V}_{o}}\ge {{V}_{E}},\ \ {{\mu }_{o}}\le {{\mu }_{E}}\]if the crystal is calcite done
clear
B)
\[{{V}_{o}}\le {{V}_{E}},\ \ {{\mu }_{o}}\le {{\mu }_{E}}\]if the crystal is quartz done
clear
C)
\[{{V}_{o}}\le {{V}_{E}},\ \ {{\mu }_{o}}\ge {{\mu }_{E}}\]if the crystal is calcite done
clear
D)
\[{{V}_{o}}\ge {{V}_{E}},\ \ {{\mu }_{o}}\ge {{\mu }_{E}}\]if the crystal is quartz done
clear
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question_answer21)
Polarising angle for water is 53°4'. If light is incident at this angle on the surface of water and reflected, the angle of refraction is [TNPCEE 2002]
A)
53°4' done
clear
B)
126°56' done
clear
C)
36°56' done
clear
D)
30°4' done
clear
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question_answer22)
When a plane polarised light is passed through an analyser and analyser is rotated through 90º, the intensity of the emerging light [TNPCEE 2002]
A)
Varies between a maximum and minimum done
clear
B)
Becomes zero done
clear
C)
Does not vary done
clear
D)
Varies between a maximum and zero done
clear
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question_answer23)
Consider the following statements A to B and identify the correct answer A. Polarised light can be used to study the helical surface of nucleic acids. B. Optics axis is a direction and not any particular line in the crystal [EAMCET (Med.) 2003]
A)
A and B are correct done
clear
B)
A and B are wrong done
clear
C)
A is correct but B is wrong done
clear
D)
A is wrong but B is correct done
clear
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question_answer24)
Two Nicols are oriented with their principal planes making an angle of 60°. The percentage of incident unpolarized light which passes through the system is
A)
50% done
clear
B)
100% done
clear
C)
12.5% done
clear
D)
37.5% done
clear
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question_answer25)
Unpolarized light falls on two polarizing sheets placed one on top of the other. What must be the angle between the characteristic directions of the sheets if the intensity of the final transmitted light is one-third the maximum intensity of the first transmitted beam
A)
75° done
clear
B)
55° done
clear
C)
35° done
clear
D)
15° done
clear
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question_answer26)
Unpolarized light of intensity 32Wm?2 passes through three polarizers such that transmission axes of the first and second polarizer makes and angle 30° with each other and the transmission axis of the last polarizer is crossed with that of the first. The intensity of final emerging light will be
A)
32 Wm?2 done
clear
B)
3 Wm?2 done
clear
C)
8 Wm?2 done
clear
D)
4 Wm?2 done
clear
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question_answer27)
In the visible region of the spectrum the rotation of the place of polarization is given by \[\theta =a+\frac{b}{{{\lambda }^{2}}}\]. The optical rotation produced by a particular material is found to be 30° per mm at \[\lambda =5000\]Å and 50° per mm at \[\lambda =4000\text{{ }\!\!\mathrm{\AA}\!\!\text{ }}\]. The value of constant a will be
A)
\[+\frac{50{}^\circ }{9}\]per mm done
clear
B)
\[-\frac{50{}^\circ }{9}\]per mm done
clear
C)
\[+\frac{9{}^\circ }{50}\]per mm done
clear
D)
\[-\frac{9{}^\circ }{50}\]per mm done
clear
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question_answer28)
When an unpolarized light of intensity \[{{I}_{0}}\] is incident on a polarizing sheet, the intensity of the light which does not get transmitted is [AIEEE 2005]
A)
Zero done
clear
B)
\[{{I}_{0}}\] done
clear
C)
\[\frac{1}{2}{{I}_{0}}\] done
clear
D)
\[\frac{1}{4}{{I}_{0}}\] done
clear
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question_answer29)
Refractive index of material is equal to tangent of polarising angle. It is called [AFMC 2005]
A)
Brewster?s law done
clear
B)
Lambert?s law done
clear
C)
Malus?s law done
clear
D)
Bragg?s law done
clear
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question_answer30)
In case of linearly polarised light, the magnitude of the electric field vector: [AIIMS 2005]
A)
Does not change with time done
clear
B)
Varies periodically with time done
clear
C)
Increases and decreases linearly with time done
clear
D)
Is parallel to the direction of propagation done
clear
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question_answer31)
When unpolarised light beam is incident from air onto glass (n = 1.5) at the polarising angle [KCET 2005]
A)
Reflected beam is polarised 100 percent done
clear
B)
Reflected and refracted beams are partially polarised done
clear
C)
The reason for (a) is that almost all the light is reflected done
clear
D)
All of the above done
clear
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question_answer32)
An optically active compound [DCE 2005]
A)
Rotates the plane polarised light done
clear
B)
Changing the direction of polarised light done
clear
C)
Do not allow plane polarised light to pass through done
clear
D)
None of the above done
clear
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question_answer33)
When the angle of incidence on a material is 60°, the reflected light is completely polarized. The velocity of the refracted ray inside the material is (in ms?1) [Kerala PMT 2005]
A)
\[3\times {{10}^{8}}\] done
clear
B)
\[\left( \frac{3}{\sqrt{2}} \right)\times {{10}^{8}}\] done
clear
C)
\[\sqrt{3}\times {{10}^{8}}\] done
clear
D)
\[0.5\times {{10}^{8}}\] done
clear
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question_answer34)
Two polaroids are placed in the path of unpolarized beam of intensity \[{{I}_{0}}\] such that no light is emitted from the second polaroid. If a third polaroid whose polarization axis makes an angle q with the polarization axis of first polaroid, is placed between these polaroids then the intensity of light emerging from the last polaroid will be [UPSEAT 2005]
A)
\[\left( \frac{{{I}_{0}}}{8} \right){{\sin }^{2}}2\theta \] done
clear
B)
\[\left( \frac{{{I}_{0}}}{4} \right){{\sin }^{2}}2\theta \] done
clear
C)
\[\left( \frac{{{I}_{0}}}{2} \right){{\cos }^{4}}\theta \] done
clear
D)
\[{{I}_{0}}{{\cos }^{4}}\theta \] done
clear
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question_answer35)
For the study of the helical structure of nucleic acids, the property of electromagnetic radiation generally used is [EAMCET 2005]
A)
Reflection done
clear
B)
Interference done
clear
C)
Diffraction done
clear
D)
Polarisation done
clear
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