MCQOPTIONS
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MCQOPTIONS
This section includes 12583 Mcqs, each offering curated multiple-choice questions to sharpen your Joint Entrance Exam - Main (JEE Main) knowledge and support exam preparation. Choose a topic below to get started.
| 11001. |
Two coherent light sources S1 and S2 (l= 6000 Å) are 1mm apart from each other. The screen is placed at a distance of 25 cm from the sources. The width of the fringes on the screen should be [CPMT 1990] |
| A. | 0.015 cm |
| B. | 0.025 cm |
| C. | 0.010 cm |
| D. | 0.030 cm |
| Answer» B. 0.025 cm | |
| 11002. |
In Young?s double slit experiment the wavelength of light was changed from 7000 Å to 3500 Å. While doubling the separation between the slits which of the following is not true for this experiment [Orissa JEE 2002] |
| A. | The width of the fringes changes |
| B. | The colour of bright fringes changes |
| C. | The separation between successive bright fringes changes |
| D. | The separation between successive dark fringes remains unchanged |
| Answer» E. | |
| 11003. |
When a thin transparent plate of thickness t and refractive index m is placed in the path of one of the two interfering waves of light, then the path difference changes by [MP PMT 2002] |
| A. | (m + 1)t |
| B. | (m ? 1)t |
| C. | \[\frac{(\mu +1)}{t}\] |
| D. | \[\frac{(\mu -1)}{t}\] |
| Answer» C. \[\frac{(\mu +1)}{t}\] | |
| 11004. |
What is the effect on Fresnel?s biprism experiment when the use of white light is made [RPMT 1998] |
| A. | Fringe are affected |
| B. | Diffraction pattern is spread more |
| C. | Central fringe is white and all are coloured |
| D. | None of these |
| Answer» D. None of these | |
| 11005. |
In Young's double-slit experiment, an interference pattern is obtained on a screen by a light of wavelength\[6000\,\,{AA}\], coming from the coherent sources S1 and S2. At certain point P on the screen third dark fringe is formed. Then the path difference S1P ? S2P in microns is [EAMCET 2003] |
| A. | 0.75 |
| B. | 1.5 |
| C. | 3 |
| D. | 4.5 |
| Answer» C. 3 | |
| 11006. |
What happens to the fringe pattern when the Young?s double slit experiment is performed in water instead or air then fringe width [AFMC 2005] |
| A. | Shrinks |
| B. | Disappear |
| C. | Unchanged |
| D. | Enlarged |
| Answer» B. Disappear | |
| 11007. |
In Young?s doubled slit experiment, the separation between the slit and the screen increases. The fringe width [BCECE 2005] |
| A. | Increases |
| B. | Decreases |
| C. | Remains unchanged |
| D. | None of these |
| Answer» B. Decreases | |
| 11008. |
A ray of light of wavelength\[{{\lambda }_{0}}\]and frequency \[{{v}_{0}}\] enters a glass slab of refractive index p, from air. Then |
| A. | its wavelength increases, frequency decreases |
| B. | its wavelength decreases, frequency remain same |
| C. | its wavelength increases, frequency remain same |
| D. | bothe remains contant |
| Answer» C. its wavelength increases, frequency remain same | |
| 11009. |
In Young's double slit experiment using monochromatic light the fringe pattern shifts by a certain distance on the screen when a mica sheet of refractive index 1.6 and thickness 1.964 microns is introduced in the path of one of the interfering waves. The mica sheet is then removed and the distance between the slits and the screen is doubled. It is found that the distance between successive maxima (or minima) now is the same as the observed fringe shift upon the introduction of the mica sheet. Calculate the wavelength of the monochromatic light used in the experiment. |
| A. | \[38.2{{A}^{o}}\] |
| B. | \[68.32{{A}^{o}}\] |
| C. | \[5892.{{A}^{o}}\] |
| D. | \[528.32{{A}^{o}}\] |
| Answer» D. \[528.32{{A}^{o}}\] | |
| 11010. |
Unpolarised light is incident on a dielectric of refractive index\[\sqrt{3}\]. What is the angle of incidence if the reflected beam is completely polarised? |
| A. | \[30{}^\circ \] |
| B. | \[45{}^\circ \] |
| C. | \[~60{}^\circ \] |
| D. | \[75{}^\circ \] |
| Answer» D. \[75{}^\circ \] | |
| 11011. |
A beam of monochromatic light is refracted from vacuum into a medium of refractive index 1.5. The wavelength of refracted light will be |
| A. | dependent on intensity of refracted light |
| B. | same |
| C. | smaller |
| D. | larger |
| Answer» D. larger | |
| 11012. |
A plane wave of monochromatic light falls normally on a uniform thin layer of oil which covers a glass plate. The wavelength of source can be varies continuously. Complete destructive interference is observed for\[\lambda =5000\overset{o}{\mathop{A}}\,\] and \[\lambda =1000\overset{o}{\mathop{A}}\,\] and for no other wavelength in between. If \[\mu \] of oil is 1.3 and that of glass is 1.5, the thickness of the film will be |
| A. | \[6.738\times {{10}^{-5}}cm\] |
| B. | \[5.7\times {{10}^{-5}}cm\] |
| C. | \[4\times {{10}^{-5}}cm\] |
| D. | \[2.8\times {{10}^{-5}}cm\] |
| Answer» B. \[5.7\times {{10}^{-5}}cm\] | |
| 11013. |
Interference fringes were produced using white light in a double slit arrangement. When a mica sheet of uniform thickness of refractive index 1.6 (relative to air) is placed in the path of light from one of the slits, the central fringe moves through some a distance. This distance is equal to the width of 30 interference bands if light of wavelength is used. The thickness \[(in\,\,\mu m)\] of mica is |
| A. | 90 |
| B. | 12 |
| C. | 14 |
| D. | 24 |
| Answer» E. | |
| 11014. |
Interference fringes were produced in Young's double slit experiment using light of wave length\[5000\text{ }\overset{o}{\mathop{A}}\,\]. When a film of material \[2.5\times {{10}^{-3}}cm\] thick was placed over one of the slits, the fringe pattern shifted by a distance equal to 20 fringe width. The refractive index of the material of the film is |
| A. | 1.25 |
| B. | 1.33 |
| C. | 1.4 |
| D. | 1.513 |
| Answer» D. 1.513 | |
| 11015. |
A parallel beam of light\[(\lambda =5000\overset{o}{\mathop{A}}\,)\]is incident at an angle \[\alpha =30{}^\circ \]with the normal to the slit plane in YDSE. Assume that the intensity due to each slit at any point on the screen is \[{{I}_{0}}\]. Point O is equidistant from \[{{S}_{1}}\] and \[{{S}_{2}}\]. The distance between slit is 1 mm, then the intensity at |
| A. | O is \[3\,{{I}_{0}}\] |
| B. | O is zero |
| C. | a point 1 m below O is \[4\,{{I}_{0}}\] |
| D. | a point on the screen 1 m below O is zero |
| Answer» D. a point on the screen 1 m below O is zero | |
| 11016. |
An optically active compound [DCE 2005] |
| A. | Rotates the plane polarised light |
| B. | Changing the direction of polarised light |
| C. | Do not allow plane polarised light to pass through |
| D. | None of the above |
| Answer» B. Changing the direction of polarised light | |
| 11017. |
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 |
| B. | Reflected and refracted beams are partially polarised |
| C. | The reason for (a) is that almost all the light is reflected |
| D. | All of the above |
| Answer» B. Reflected and refracted beams are partially polarised | |
| 11018. |
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 |
| B. | Becomes zero |
| C. | Does not vary |
| D. | Varies between a maximum and zero |
| Answer» E. | |
| 11019. |
In case of linearly polarised light, the magnitude of the electric field vector: [AIIMS 2005] |
| A. | Does not change with time |
| B. | Varies periodically with time |
| C. | Increases and decreases linearly with time |
| D. | Is parallel to the direction of propagation |
| Answer» C. Increases and decreases linearly with time | |
| 11020. |
Refractive index of material is equal to tangent of polarising angle. It is called [AFMC 2005] |
| A. | Brewster?s law |
| B. | Lambert?s law |
| C. | Malus?s law |
| D. | Bragg?s law |
| Answer» B. Lambert?s law | |
| 11021. |
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 |
| B. | \[{{I}_{0}}\] |
| C. | \[\frac{1}{2}{{I}_{0}}\] |
| D. | \[\frac{1}{4}{{I}_{0}}\] |
| Answer» D. \[\frac{1}{4}{{I}_{0}}\] | |
| 11022. |
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 |
| B. | \[-\frac{50{}^\circ }{9}\]per mm |
| C. | \[+\frac{9{}^\circ }{50}\]per mm |
| D. | \[-\frac{9{}^\circ }{50}\]per mm |
| Answer» C. \[+\frac{9{}^\circ }{50}\]per mm | |
| 11023. |
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. | 0.5 |
| B. | 1 |
| C. | 0.125 |
| D. | 0.375 |
| Answer» D. 0.375 | |
| 11024. |
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 |
| B. | A and B are wrong |
| C. | A is correct but B is wrong |
| D. | A is wrong but B is correct |
| Answer» B. A and B are wrong | |
| 11025. |
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 |
| B. | Two stationary dots |
| C. | Two rotating dots |
| D. | One dot rotating about the other |
| Answer» E. | |
| 11026. |
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 |
| B. | Refraction of light |
| C. | Polarisation of light |
| D. | Dispersion of light |
| Answer» D. Dispersion of light | |
| 11027. |
In the propagation of electromagnetic waves the angle between the direction of propagation and plane of polarisation is [CPMT 1978] |
| A. | 0o |
| B. | 45o |
| C. | 90o |
| D. | 180o |
| Answer» B. 45o | |
| 11028. |
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 |
| B. | Horizontal plane |
| C. | Plane making an angle of 45o with the vertical |
| D. | Plane making an angle of 57o with the horizontal |
| Answer» B. Horizontal plane | |
| 11029. |
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. | \[90+\varphi \] |
| B. | \[{{\sin }^{-1}}(\mu \cos \varphi )\] |
| C. | 90o |
| D. | \[{{90}^{o}}-{{\sin }^{-1}}(\sin \varphi /\mu )\] |
| Answer» D. \[{{90}^{o}}-{{\sin }^{-1}}(\sin \varphi /\mu )\] | |
| 11030. |
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 |
| B. | Nicol's prism works on the principle of double refraction and total internal reflection |
| C. | Nicol's prism can be used to produce and analyze polarized light |
| D. | Calcite and Quartz are both doubly refracting crystals |
| Answer» B. Nicol's prism works on the principle of double refraction and total internal reflection | |
| 11031. |
Light waves can be polarised as they are [CBSE PMT 1993; KCET 1994; AFMC 1997; J & K CET 2002; CPMT 2005] |
| A. | Transverse |
| B. | Of high frequency |
| C. | Longitudinal |
| D. | Reflected |
| Answer» B. Of high frequency | |
| 11032. |
A polariser is used to [CPMT 1999] |
| A. | Reduce intensity of light |
| B. | Produce polarised light |
| C. | Increase intensity of light |
| D. | Produce unpolarised light |
| Answer» C. Increase intensity of light | |
| 11033. |
In a two-slit experiment with white light, a white fringe is observed on a screen kept behind the slits. When the screen in moved away by 0.05 m, this white fringe |
| A. | Does not move at all |
| B. | Gets displaced from its earlier position |
| C. | Becomes colored |
| D. | Disappears |
| Answer» B. Gets displaced from its earlier position | |
| 11034. |
The wave front of a light beam is given by the equation \[x+2y+3x=c\](where c is arbitrary constant), then the angle made by the direction of light with the y-axis is |
| A. | \[{{\cos }^{-1}}\frac{1}{\sqrt{14}}\] |
| B. | \[{{\sin }^{-1}}\frac{2}{\sqrt{14}}\] |
| C. | \[{{\cos }^{-1}}\frac{2}{\sqrt{14}}\] |
| D. | \[{{\sin }^{-1}}\frac{3}{\sqrt{14}}\] |
| Answer» D. \[{{\sin }^{-1}}\frac{3}{\sqrt{14}}\] | |
| 11035. |
In a standard Young's double-slit experiment with coherent light of wavelength 600 nm, the fringe width of the fringes in the central region (near the central fringe,\[{{P}_{0}}\]) is observed to be 3 mm. An extremely thin glass plate ' is introduced in front of the first slit, and the fringes are observed to be displaced by 11 mm. Another thin plate is placed before the second slit and it is observed that the fringes are now displaced by an additional 12 mm. If the additional optical path lengths introduced are \[{{\Delta }_{1}}\] and \[{{\Delta }_{2}}\] then |
| A. | \[11{{\Delta }_{1}}=12{{\Delta }_{2}}\] |
| B. | \[12{{\Delta }_{1}}=11{{\Delta }_{2}}\] |
| C. | \[11{{\Delta }_{1}}>12{{\Delta }_{2}}\] |
| D. | None of the above |
| Answer» C. \[11{{\Delta }_{1}}>12{{\Delta }_{2}}\] | |
| 11036. |
In Young's double-slit experiment, the angular width of a fringe formed on a distant screen is \[1{}^\circ .\] The wavelength of light used is\[6000\,\,\overset{\text{o}}{\mathop{\text{A}}}\,\]. What is the spacing between the slits? |
| A. | 344 mm |
| B. | 0.1344 mm |
| C. | 0.0344 mm |
| D. | 0.034 mm |
| Answer» D. 0.034 mm | |
| 11037. |
A star emitting radiation at a wavelength of \[5000\,{AA}\] is approaching earth with a velocity of\[1.5\times {{10}^{6}}m/s\]. The change in wavelength of the radiation as received on the earth, is [CBSE PMT 1995] |
| A. | \[25\,\,{AA}\] |
| B. | Zero |
| C. | \[100\,\,{AA}\] |
| D. | \[2.5\,\,{AA}\] |
| Answer» B. Zero | |
| 11038. |
If a source of light is moving away from a stationary observer, then the frequency of light wave appears to change because of [AFMC 1995] |
| A. | Doppler's effect |
| B. | Interference |
| C. | Diffraction |
| D. | None of these |
| Answer» B. Interference | |
| 11039. |
In order to see diffraction the thickness of the film is [J&K CEE 2001] |
| A. | \[100\,\,{AA}\] |
| B. | \[10,000\,\,{AA}\] |
| C. | 1 mm |
| D. | 1 cm |
| Answer» C. 1 mm | |
| 11040. |
Direction of the first secondary maximum in the Fraunhofer diffraction pattern at a single slit is given by (a is the width of the slit) [KCET 1999] |
| A. | \[a\sin \theta =\frac{\lambda }{2}\] |
| B. | \[a\cos \theta =\frac{3\lambda }{2}\] |
| C. | \[a\sin \theta =\lambda \] |
| D. | \[a\sin \theta =\frac{3\lambda }{2}\] |
| Answer» E. | |
| 11041. |
Diffraction effects are easier to notice in the case of sound waves than in the case of light waves because [RPET 1978; KCET 1994, 2000] |
| A. | Sound waves are longitudinal |
| B. | Sound is perceived by the ear |
| C. | Sound waves are mechanical waves |
| D. | Sound waves are of longer wavelength |
| Answer» E. | |
| 11042. |
When the wavelength of light coming from a distant star is measured it is found shifted towards red. Then the conclusion is [JIPMER 1999] |
| A. | The star is approaching the observer |
| B. | The star recedes away from earth |
| C. | There is gravitational effect on the light |
| D. | The star remains stationary |
| Answer» C. There is gravitational effect on the light | |
| 11043. |
A rocket is going away from the earth at a speed 0.2c, where c = speed of light. It emits a signal of frequency \[4\times {{10}^{7}}Hz\]. What will be the frequency observed by an observer on the earth [RPMT 1996] |
| A. | \[4\times {{10}^{6}}Hz\] |
| B. | \[3.2\times {{10}^{7}}Hz\] |
| C. | \[3\times {{10}^{6}}Hz\] |
| D. | \[5\times {{10}^{7}}Hz\] |
| Answer» C. \[3\times {{10}^{6}}Hz\] | |
| 11044. |
In an interference arrangement similar to Young's double slit experiment, the slits S1 and S2 are illuminated with coherent microwave sources each of frequency 106 Hz. The sources are synchronized to have zero phase difference. The slits are separated by distance d = 150 m. The intensity I\[(\theta )\]is measured as a function ofq, where q is defined as shown. If I0 is maximum intensity, then \[I(\theta )\] for \[0\le \theta \le {{90}^{o}}\]is given by [IIT 1995] |
| A. | \[I(\theta )={{I}_{0}}\]for \[\theta ={{0}^{o}}\] |
| B. | \[I(\theta )={{I}_{0}}/2\]for \[\theta ={{30}^{o}}\] |
| C. | \[I(\theta )={{I}_{0}}/4\]for \[\theta ={{90}^{o}}\] |
| D. | \[I(\theta )\] is constant for all values of q |
| Answer» C. \[I(\theta )={{I}_{0}}/4\]for \[\theta ={{90}^{o}}\] | |
| 11045. |
In Young's double slit experiment the y-coordinates of central maxima and 10th maxima are 2 cm and 5 cm respectively. When the YDSE apparatus is immersed in a liquid of refractive index 1.5 the corresponding y-coordinates will be |
| A. | 2 cm, 7.5 cm |
| B. | 3 cm, 6 cm |
| C. | 2 cm, 4 cm |
| D. | 4/3 cm, 10/3 cm |
| Answer» D. 4/3 cm, 10/3 cm | |
| 11046. |
Four light waves are represented by (i) y = a1 sinw t (ii) \[y={{a}_{2}}\sin (\omega \,t+\varphi )\] (iii) \[y={{a}_{1}}\sin 2\omega \,t\] (iv) \[y={{a}_{2}}\sin 2(\,\omega \,t+\varphi )\] Interference fringes may be observed due to superposition of |
| A. | (i) and (ii) |
| B. | (i) and (iii) |
| C. | (ii) and (iv) |
| D. | (iii) and (iv) |
| Answer» E. | |
| 11047. |
A string fixed at both the ends is vibrating in two segments. The wavelength of the corresponding wave is [SCRA 1994] |
| A. | \[\frac{l}{4}\] |
| B. | \[\frac{l}{2}\] |
| C. | l |
| D. | 2l |
| Answer» D. 2l | |
| 11048. |
A 1 cm long string vibrates with fundamental frequency of 256 Hz. If the length is reduced to \[\frac{1}{4}cm\] keeping the tension unaltered, the new fundamental frequency will be [BHU 1997] |
| A. | 64 |
| B. | 256 |
| C. | 512 |
| D. | 1024 |
| Answer» E. | |
| 11049. |
The frequency of transverse vibrations in a stretched string is 200 Hz. If the tension is increased four times and the length is reduced to one-fourth the original value, the frequency of vibration will be [EAMCET (Med.) 1999] |
| A. | 25 Hz |
| B. | 200 Hz |
| C. | 400 Hz |
| D. | 1600 Hz |
| Answer» E. | |
| 11050. |
Three similar wires of frequency n1, n2 and n3 are joined to make one wire. Its frequency will be [CBSE PMT 2000] |
| A. | \[n={{n}_{1}}+{{n}_{2}}+{{n}_{3}}\] |
| B. | \[\frac{1}{n}=\frac{1}{{{n}_{1}}}+\frac{1}{{{n}_{2}}}+\frac{1}{{{n}_{3}}}\] |
| C. | \[\frac{1}{\sqrt{n}}=\frac{1}{\sqrt{{{n}_{1}}}}+\frac{1}{\sqrt{{{n}_{2}}}}+\frac{1}{\sqrt{{{n}_{3}}}}\] |
| D. | \[\frac{1}{{{n}^{1}}}=\frac{1}{n_{1}^{2}}+\frac{1}{n_{2}^{2}}+\frac{1}{n_{3}^{2}}\] |
| Answer» C. \[\frac{1}{\sqrt{n}}=\frac{1}{\sqrt{{{n}_{1}}}}+\frac{1}{\sqrt{{{n}_{2}}}}+\frac{1}{\sqrt{{{n}_{3}}}}\] | |