JEE Main & Advanced Physics Wave Optics / तरंग प्रकाशिकी Question Bank

done Self Evaluation Test - Wave Optics Total Questions - 100

• question_answer1)
  Huygen's concept of secondary wave
  A)
  allows us to find the focal length of a thick lens done clear
  B)
  is a geometrical method to find a wave front done clear
  C)
  is used to determine the velocity of light done clear
  D)
  is used to explain polarization done clear
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• question_answer2)
  A wave front AB passing through a system C emerges as DE. The system C could be            
  A)
  a slit done clear
  B)
  a biprism      done clear
  C)
  a prism done clear
  D)
  a glass slab     done clear
  View Solution play_arrow

• question_answer3)
  The phase difference between incident wave and reflected wave is \[180{}^\circ \] when light ray
  A)
  enters into glass from air done clear
  B)
  enters into air from glass  done clear
  C)
  enters into glass from diamond done clear
  D)
  enters into water from glass done clear
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• question_answer4)
  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 done clear
  B)
  same done clear
  C)
  smaller done clear
  D)
  larger done clear
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• question_answer5)
  The correct curve between refractive index p, and wavelength\[\lambda \] will be              
  A)
  A done clear
  B)
  D                   done clear
  C)
  B  done clear
  D)
  C      done clear
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• question_answer6)
     A double slit arrangement produces fringes for  \[\lambda =5890\overset{o}{\mathop{A}}\,\] that are \[0.4{}^\circ \] apart. What is the angular width if the entire arrangement is immersed in water? \[({{\mu }_{w}}=4/3)\]
  A)
  \[0.3{}^\circ \]  done clear
  B)
  \[2.3{}^\circ \]   done clear
  C)
  \[0.8{}^\circ \]  done clear
  D)
  \[1.3{}^\circ \] done clear
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• question_answer7)
  Young's double slit experiment is made in a liquid. The \[{{10}^{th}}\] bright fringe lies in liquid where \[{{6}^{th}}\] dark fringe lies in vacuum. The refractive index of the liquid is approximately     
  A)
  1.8    done clear
  B)
  1.5    done clear
  C)
  1.3  done clear
  D)
  1.6 done clear
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• question_answer8)
  A possible means for making an airplane invisible to radar is to coat the plane with an anti-reflective polymer. Radar waves have a wavelength of 3.00 cm and the index of refraction of the polymer is n=1.50. How thick would you make the coating?
  A)
  1.50cm done clear
  B)
  3.00cm done clear
  C)
  0.50cm done clear
  D)
  None of these done clear
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• question_answer9)
  In the adjacent diagram, CP represents a wave front and AO & BP, the corresponding two rays. Find the condition on 0 tor constructive interference at P between the ray BP and reflected ray OP.
  A)
  \[\cos \theta =3\lambda /2d\]      done clear
  B)
  \[\cos \theta =\lambda /4d\] done clear
  C)
  \[\sec \theta -\cos \theta =\lambda /d\]      done clear
  D)
  \[\sec \theta -\cos \theta =4\lambda /d\] done clear
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• question_answer10)
  From a medium of index of refraction\[{{n}_{1}}\], monochromatic light of wavelength \[\lambda \] is incident normally on a thin film of uniform thickness L \[(where\,\,L>0.1\lambda )\] and index of refraction \[{{n}_{2}}\]. The light transmitted by the film travels into a medium with refractive index \[{{n}_{3}}\].The value of minimum film thickness when maximum light is transmitted If \[({{n}_{1}}<{{n}_{2}}<{{n}_{3}})\] is
  A)
  \[\frac{{{n}_{1}}\lambda }{2{{n}_{2}}}\] done clear
  B)
  \[\frac{{{n}_{1}}\lambda }{4{{n}_{2}}}\] done clear
  C)
  \[\frac{\lambda }{4{{n}_{2}}}\] done clear
  D)
  \[\frac{\lambda }{2{{n}_{2}}}\] done clear
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• question_answer11)
  Two slits separated by a distance of 1 mm are illuminated with red light of wavelength\[6.5\times {{10}^{-7}}m\]. The interference fringes are observed on a screen placed 1 m from the silts. The distance of the third dark fringe from the central fringe will be equal to:               
  A)
  0.65 mm done clear
  B)
  1.30mm done clear
  C)
  1.62 mm done clear
  D)
  1.95mm done clear
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• question_answer12)
  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   done clear
  B)
  1.33   done clear
  C)
  1.4    done clear
  D)
  1.513 done clear
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• question_answer13)
  In an interference arrangement similar to Young's double-slit experiment, the slits \[{{S}_{1}}\] and \[{{S}_{2}}\] 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 a distance d = 150.0 m. The intensity I \[\left( \theta  \right)\] is measured as a function of \[\theta \], where \[\theta \] is defined as shown. If \[{{I}_{0}}\] is the maximum intensity, then I\[\left( \theta  \right)\] for \[\] is given by  
  A)
  \[I(\theta )={{I}_{0}}/2\] for \[\theta ={{30}^{o}}\] done clear
  B)
  \[I(\theta )={{I}_{0}}/4\] for\[\theta ={{90}^{o}}\] done clear
  C)
  \[I(\theta )={{I}_{0}}\] for \[\theta ={{0}^{o}}\] done clear
  D)
  \[I=\theta \] is constant for all values of \[\theta \] done clear
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• question_answer14)
  If white light is used in the Newton's rings experiment, the colour observed in the reflected light is complementary to that observed in the transmitted light through the same point. This is due to
  A)
  \[90{}^\circ \] change of phase in one of the reflected waves done clear
  B)
  \[180{}^\circ \]change of phase in one of the reflected waves done clear
  C)
  \[145{}^\circ \]change of phase in one of the reflected waves done clear
  D)
  \[45{}^\circ \]change of phase in one of the reflected waves done clear
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• question_answer15)
  In Fresnel's biprism experiment the width of 10 fringes is 2cm which are formed at a distance of 2 meter from the slit. If the wavelength of light is \[5100\overset{o}{\mathop{A}}\,\] then the distance between two coherent  sources will be
  A)
  \[5.1\times {{10}^{-4}}m\] done clear
  B)
  \[5.1\times {{10}^{4}}m\] done clear
  C)
  \[5.1\times {{10}^{-4}}mm\] done clear
  D)
  \[10.1\times {{10}^{-4}}cm\] done clear
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• question_answer16)
  Two beams of light having intensities I and 4I interfere to produce a fringe pattern on a screen. The phase difference between the beams is\[\pi /2\] at point A and n at point B. Then the difference between the resultant intensities at\[\pi \] and B is
  A)
  \[2I\] done clear
  B)
  \[4I\] done clear
  C)
  \[5I\]  done clear
  D)
  \[7I\] done clear
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• question_answer17)
  In the ideal double-slit experiment, when a glass- plate (refractive index 1.5) of thickness t is introduced in the path of one of the interfering beams \[(wave-lenght\lambda )\], the intensity at the position where the central maximum occurred previously remains unchanged. The minimum thickness of the glass-plate is
  A)
  \[2\lambda \]  done clear
  B)
  \[2\lambda /3\] done clear
  C)
  \[\lambda /3\] done clear
  D)
  \[\lambda \] done clear
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• question_answer18)
  Monochromatic light of wavelength 400 nm and 560 nm are incident simultaneously and normally on double slits apparatus whose slits separation is 0.1 mm and screen distance is 1m. Distance between areas of total darkness will be
  A)
  4mm done clear
  B)
  5.6 mm done clear
  C)
  14mm done clear
  D)
  28mm done clear
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• question_answer19)
  White light used to illuminate the two slits in Young's double slit experiment. The separation between the slits is d and the distance between the screen and the slit is D(>>d). At a point on the screen in front of one of the slits, certain wave- lengths are missing. The missing wavelengths are
  A)
  \[\lambda =\frac{{{d}^{2}}}{(2n+1)D}\] done clear
  B)
  \[\lambda =\frac{(2n+1){{d}^{2}}}{D}\] done clear
  C)
  \[\lambda =\frac{{{d}^{2}}}{(n+1)D}\] done clear
  D)
  \[\lambda =\frac{(n+1)D}{{{d}^{2}}}\] done clear
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• question_answer20)
  A thin slice is cut out of a glass cylinder along a plane parallel to its axis. The slice is placed on a flat glass plate as shown in Figure. The observed interference fringes from this combination shall be                  
  A)
  straight done clear
  B)
  circular              done clear
  C)
  equally spaced     done clear
  D)
  having fringe spacing which increases as we go outwards done clear
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• question_answer21)
  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    done clear
  B)
  12    done clear
  C)
  14    done clear
  D)
  24 done clear
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• question_answer22)
  In a Young's double slit experiment, 12 fringes are observed to be formed in a certain segment of the screen when light of wavelength 600 nm is used. If the wavelength of light is changed to 400 nm, number of fringes observed in the same segment of the screen is given by
  A)
  12   done clear
  B)
  18    done clear
  C)
  24    done clear
  D)
  30 done clear
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• question_answer23)
  Two monochromatic light beams of intensity 16 and 9 units are interfering. The ratio of intensities of bright and dark parts of the resultant pattern is:
  A)
  \[\frac{16}{9}\] done clear
  B)
  \[\frac{7}{1}\] done clear
  C)
  \[\frac{7}{1}\] done clear
  D)
  \[\frac{49}{1}\] done clear
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• question_answer24)
  In Young's double slit experiment intensity at a point is (1/4) of the maximum intensity. Angular position of this point is
  A)
  \[{{\sin }^{-1}}(\lambda /d)\] done clear
  B)
  \[{{\sin }^{-1}}(\lambda /2d)\] done clear
  C)
  \[{{\sin }^{-1}}(\lambda /3d)\] done clear
  D)
  \[{{\sin }^{-1}}(\lambda /4d)\] done clear
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• question_answer25)
  A thin sheet of mica (\[\mu \] m thick) is placed in the path of one of the interfering beams in a biprism arrangement. It is found that the central bright band shifts a distance equal to the width of a bright fringe. The refractive index of mica \[(Given\,\,\lambda =6\times {{10}^{-7}}\,m)\] is
  A)
  1.0   done clear
  B)
  1.5    done clear
  C)
  1.75 done clear
  D)
  1.25 done clear
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• question_answer26)
  Two sources \[{{S}_{1}}\] and \[{{S}_{2}}\] emitting coherent light waves of wavelength \[\lambda \] in the same phase are situated as shown. The distance OP, so that the light intensity detected at P is equal to that at O is       
  A)
  \[D\sqrt{2}\] done clear
  B)
  \[D/2\] done clear
  C)
   \[D\sqrt{3}\] done clear
  D)
  \[D/\sqrt{3}\] done clear
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• question_answer27)
  When a plastic thin film of refractive index 1.45 is placed in the path of one of the interfering waves then the central fringe is displaced through width of five fringes. The thickness of the film, if the wavelength of light is \[5890\,\overset{o}{\mathop{A}}\,\], will be
  A)
  \[6.544\times {{10}^{-4}}cm\]   done clear
  B)
  \[6.544\times {{10}^{-4}}m\] done clear
  C)
  \[6.54\times {{10}^{-4}}cm\]   done clear
  D)
  \[6.5\times {{10}^{-4}}cm\] done clear
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• question_answer28)
  A plastic sheet (refractive index =1.6) covers one slit of a double slit arrangement meant for the Young's experiment. When the double slit is illuminated by monochromatic light (wavelength in air\[=6600\,\overset{o}{\mathop{A}}\,\]), the centre of the screen appears dark rather than bright. The minimum thickness of the plastic sheet to be used for this to happen is:
  A)
  \[3300\overset{o}{\mathop{A}}\,\] done clear
  B)
  \[6600\overset{o}{\mathop{A}}\,\] done clear
  C)
  \[2062\overset{o}{\mathop{A}}\,\] done clear
  D)
  \[5500\overset{o}{\mathop{A}}\,\] done clear
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• question_answer29)
  The YDSE apparatus is as shown in Fig. The condition for point P to be a dark fringe is
  A)
  \[({{l}_{1}}-{{l}_{3}})+({{l}_{2}}-{{l}_{4}})=n\lambda \] done clear
  B)
  \[({{l}_{1}}-{{l}_{2}})+({{l}_{3}}-{{l}_{4}})=\frac{(2n-1)}{2}\lambda \] done clear
  C)
  \[({{l}_{1}}-{{l}_{3}})+({{l}_{2}}-{{l}_{4}})=\frac{(2n-1)\lambda }{2}\] done clear
  D)
  \[({{l}_{1}}-{{l}_{2}})+({{l}_{4}}-{{l}_{3}})=\frac{(2n-1)\lambda }{2}\] done clear
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• question_answer30)
  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)
  \[6.738\times {{10}^{-5}}cm\]    done clear
  B)
  \[5.7\times {{10}^{-5}}cm\] done clear
  C)
  \[4\times {{10}^{-5}}cm\]       done clear
  D)
         \[2.8\times {{10}^{-5}}cm\] done clear
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• question_answer31)
  A broad source of light (I= 680 nm) illuminates normally two glass plates 120 mm long that touch at one end and are separated by a wire 0.034 mm in diameter at the other end. The total number of bright fringes that appear over the 120 mm distance is-        
  A)
  50 done clear
  B)
  100 done clear
  C)
  200 done clear
  D)
  400 done clear
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• question_answer32)
  Two light waves having the same wavelength\[\lambda \] in vacuum are in phase initially. Then the first ray travels a path of length \[{{L}_{1}}\] through a medium of refractive index \[{{\mu }_{1}}\]. The second ray travels a path of length \[{{L}_{2}}\] through a medium of refractive index\[{{\mu }_{2}}\]. The two waves are then combined to observe interference effects. The phase difference between the two, when they interfere, is
  A)
  \[\frac{2\pi }{\lambda }({{L}_{1}}-{{L}_{2}})\] done clear
  B)
  \[\frac{2\pi }{\lambda }({{\mu }_{1}}{{L}_{1}}-{{\mu }_{2}}{{L}_{2}})\] done clear
  C)
  \[\frac{2\pi }{\lambda }({{\mu }_{2}}{{L}_{1}}-{{\mu }_{1}}{{L}_{2}})\] done clear
  D)
  \[\frac{2\pi }{\lambda }\left[ \frac{{{L}_{1}}}{{{\mu }_{1}}}-\frac{{{L}_{2}}}{{{\mu }_{2}}} \right]\] done clear
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• question_answer33)
  In YSDE, both slits are covered by transparent slab. Upper slit is covered by slab of R.I. 1.5 and thickness t and lower is covered by R.I. \[\frac{4}{3}\] and thickness 2t, then central maxima
  A)
  shifts in +ve y-axis direction done clear
  B)
  shifts in -ve  y-axis direction done clear
  C)
  remains at same position done clear
  D)
  may shift in upward or downward depending upon wavelength of light done clear
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• question_answer34)
  A light of wavelength \[6000\overset{o}{\mathop{A}}\,\] shines on two narrow slits separated by a distance 1.0 mm and illuminates a screen at a distance 1.5 m away. When one slit is covered by a thin glass plate of refractive index 1.8 and other slit by a thin glass plate of refractive index\[\mu \], the central maxima shifts by 0.1 rad. Both plates have the same thickness of 0.5 mm. The value of refractive index \[\mu \]of the glass is          
  A)
  1.4  done clear
  B)
  l5 done clear
  C)
  1.6 done clear
  D)
  None of these done clear
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• question_answer35)
  In Young's double slit experiment intensity at a point is how much times of the maximum intensity if angular position of this point is\[{{\sin }^{-1}}(\lambda /6d)\]?
  A)
  \[1/2\]  done clear
  B)
  \[2/5\] done clear
  C)
  \[3/4\] done clear
  D)
  \[3/5\] done clear
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• question_answer36)
  A monochromatic light is used in Young's double slit experiment when one of the slits is covered by a transparent sheet of thickness 1.8 mm, made of material of refractive index \[{{\mu }_{1}}\]number of fringes which shift is 18, when another sheet of thickness 3.6 mm, made of material of refractive index \[{{\mu }_{2}}\]is used, number of fringes which shift is 9. Relation between \[{{\mu }_{1}}\] and \[{{\mu }_{2}}\] is given by
  A)
  \[4{{\mu }_{2}}-{{\mu }_{1}}=3\] done clear
  B)
  \[4{{\mu }_{1}}-{{\mu }_{2}}=3\] done clear
  C)
  \[3{{\mu }_{2}}-{{\mu }_{1}}=4\] done clear
  D)
  \[2{{\mu }_{1}}-{{\mu }_{2}}=4\] done clear
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• question_answer37)
  Two coherent sources separated by distance d are radiating in phase having wavelength X. A detector moves in a big circle around the two sources in the plane of the two sources. The angular position n=4 interference maxima is given as
  A)
  \[{{\sin }^{-1}}\frac{n\lambda }{d}\] done clear
  B)
  \[{{\cos }^{-1}}\frac{4\lambda }{d}\] done clear
  C)
  \[{{\tan }^{-1}}\frac{d}{4\lambda }\] done clear
  D)
  \[{{\cos }^{-1}}\frac{\lambda }{4d}\] done clear
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• question_answer38)
  A glass plate 0.40 micron thick is illuminated by a beam of white light normal to the plate. The refractive index of glass is 1.50 and the limits of the visible spectrum are \[{{\lambda }_{V}}=4000\,\overset{o}{\mathop{A}}\,\] and\[{{\lambda }_{R}}=7000\,\overset{o}{\mathop{A}}\,\] The wavelengths that get intensified in the reflected beam are
  A)
  \[\text{4800 }\overset{o}{\mathop{A}}\,\]and \[5200\overset{o}{\mathop{A}}\,\]   done clear
  B)
  \[4800\overset{o}{\mathop{A}}\,\]and \[6700\overset{o}{\mathop{A}}\,\] done clear
  C)
  \[4800\overset{o}{\mathop{A}}\,\]only   done clear
  D)
  \[5200\overset{o}{\mathop{A}}\,\]only done clear
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• question_answer39)
  In a YDSE experiment if a slab whose refraction index can be varied is placed in front of one of the slits then the variation of resultant intensity at mid-point of screen with 'u' will be best represented by \[(\mu \ge 1)\]. [Assume slits of equal width and there is no absorption by slab; midpoint of screen is the point where waves interfere with zero phase difference in absence of slab]               
  A)
         done clear
  B)
  done clear
  C)
  done clear
  D)
  done clear
  View Solution play_arrow

• question_answer40)
  In an experiment, sodium light \[|\mu -1.8|t.\] is employed and interference fringes are obtained in which 20 fringes equally spaced occupy 2.30 cm on the screen. When sodium light is replaced by blue light, the setup remaining the same otherwise, 30 fringes occupy 2.80 cm. The wavelength of blue light is
  A)
  \[4780\overset{o}{\mathop{A}}\,\] done clear
  B)
  \[5760\overset{o}{\mathop{A}}\,\] done clear
  C)
  \[9720\,\overset{o}{\mathop{A}}\,\] done clear
  D)
  \[6390\overset{o}{\mathop{A}}\,\] done clear
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• question_answer41)
  A ray of light of intensity I is incident on a parallel glass slab at point A as shown in diagram. It undergoes partial reflection and refraction. At each reflection, 25% of incident energy is reflected. The rays AB and A'B' undergo interference. The ratio of\[{{I}_{\max }}\]and\[{{I}_{\min }}\]is:     
  A)
  49 : 1 done clear
  B)
  7 : 1   done clear
  C)
  4 : 1   done clear
  D)
  8 : 1 done clear
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• question_answer42)
  A wedged shaped air film having an angle of 40 second is illuminated by a monochromatic light and the fringes are observed vertically down through a microscope. The fringe separation between two consecutive bright fringes is 0.12 cm. The wavelength of light is:
  A)
  \[~5545\overset{o}{\mathop{A}}\,\] done clear
  B)
  \[6025\overset{o}{\mathop{A}}\,\] done clear
  C)
  \[4925\overset{o}{\mathop{A}}\,\] done clear
  D)
  \[~4655\overset{o}{\mathop{A}}\,\] done clear
  View Solution play_arrow

• question_answer43)
  Figure shows two coherent sources \[{{S}_{1}}-{{S}_{2}}\] vibrating in same phase. AB is an irregular wire lying at a far distance from the sources \[{{S}_{1}}\] and \[{{S}_{2}}\].Let\[\frac{\lambda }{d}={{10}^{-3}}\].\[\angle BOA={{0.12}^{o}}\] . How many bright spots will be seen on the wire, including points A and B.  
  A)
  2 done clear
  B)
  3 done clear
  C)
  4 done clear
  D)
  more than 4      done clear
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• question_answer44)
           In young's double - slit experiment, the separation between the slits is d, distance between the slit and screen is D (D>>d). In the interference pattern, there is a maxima exactly in front of each slit. Then the possible wavelength(s) used in the experiment are        
  A)
  \[{{d}^{2}}/D,\,{{d}^{2}}/2D,\,{{d}^{2}}/3D\] done clear
  B)
  \[{{d}^{2}}/D,\,{{d}^{2}}/3D,\,{{d}^{2}}/5D\] done clear
  C)
  \[{{d}^{2}}/2D,\,{{d}^{2}}/4D,\,{{d}^{2}}/6D\] done clear
  D)
  None of these done clear
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• question_answer45)
  A YDSE is conducted in water\[({{\mu }_{1}})\] as shown in figure. A glass plate of thickness t and refractive index\[{{\mu }_{2}}\] is placed in the path of \[{{S}_{2}}\]. The optical path difference at O is
  A)
  \[({{\mu }_{2}}-1)t\] done clear
  B)
  \[({{\mu }_{1}}-1)t\] done clear
  C)
  \[\left( \frac{{{\mu }_{2}}}{{{\mu }_{1}}}-1 \right)t\] done clear
  D)
  \[({{\mu }_{2}}-{{\mu }_{1}})t\] done clear
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• question_answer46)
  In a Young's double slit experiment with light of wavelength \[\beta \], fringe pattern on the screen has fringe width\[\beta \]. When two thin transparent glass (refractive index u) plates of thickness\[{{t}_{1}}\] and\[{{t}_{2}}\]\[({{t}_{1}}>{{t}_{2}})\] are placed in the path of the two beams respectively, the fringe pattern will shift by a distance
  A)
  \[\frac{\beta (\mu -1)}{\lambda }\left( \frac{{{t}_{1}}}{{{t}_{2}}} \right)\] done clear
  B)
  \[\frac{\mu \beta }{\lambda }\frac{{{t}_{1}}}{{{t}_{2}}}\] done clear
  C)
  \[\frac{\beta (\mu -1)}{\lambda }({{t}_{1}}-{{t}_{2}})\] done clear
  D)
  \[(\mu -1)\frac{\lambda }{\beta }({{t}_{1}}+{{t}_{2}})\] done clear
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• question_answer47)
  Two identical coherent sources are placed on a diameter of a circle of radius R at separation x (<< R) symmetrical about the center of the circle. The sources emit identical wavelength\[\lambda \] each. The number of points on the circle of maximum intersity is\[(x=5\lambda )\]    
  A)
  20 done clear
  B)
  22    done clear
  C)
  24 done clear
  D)
  26 done clear
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• question_answer48)
  To produce a minimum reflection of wavelengths near the middle of visible spectrum (550 nm), how thick should a coating of\[Mg{{F}_{2}}\,(\mu =1.38)\]coated on a glass surface?
  A)
  \[{{10}^{-7}}\] done clear
  B)
  \[{{10}^{-10}}\] done clear
  C)
  \[{{10}^{-9}}m\] done clear
  D)
  \[{{10}^{-8}}m\] done clear
  View Solution play_arrow

• question_answer49)
  In YDSE distance between the \[{{S}_{1}}\]and\[{{S}_{2}}\]is d. \[{{P}_{1}}\]and\[{{P}_{2}}\]are two points equidistance from O at an angular position \[\beta \]as shown. A parallel beam of monochromatic light is incident at an angle a on the slits. Then the ratio of path difference at\[{{P}_{1}}\]and\[{{P}_{2}}\]is:
  A)
  \[\cot \frac{\alpha -\beta }{2}\cot \frac{\alpha +\beta }{2}\]          done clear
  B)
  \[\tan \frac{\alpha +\beta }{2}\cot \frac{\alpha -\beta }{2}\] done clear
  C)
  \[\sin \frac{\alpha +\beta }{2}\cos \frac{\alpha -\beta }{2}\]           done clear
  D)
  \[\tan \frac{\alpha -\beta }{2}\cot \frac{\alpha +\beta }{2}\] done clear
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• question_answer50)
  A physics professor wants to find the diameter of a human hair by placing it between two flat glass plates, illuminating the plates with light of vacuum wavelength\[\lambda =552nm\]and counting the number of bright fringes produced along the plates. The Professor find 125 bright fringes between the edge of the plates and the hair. What is the diameter of the hair? 
  A)
  \[525\times {{10}^{-9}}m\] done clear
  B)
  \[344\times {{10}^{-3}}m\] done clear
  C)
  \[3.44\times {{10}^{-5}}m\] done clear
  D)
  None of the above done clear
  View Solution play_arrow

• question_answer51)
  In the figure shown in a YDSE, a parallel beam of light is incident on the slits from a medium of refractive index \[{{n}_{1}}\].The wavelength of light in this medium is\[{{\lambda }_{1}}\]. A transparent slab of thickness t and refractive index is put in front of one slit. The medium between the screen and the plane of the slits is \[{{n}_{2}}\]. The phase difference between the light waves reaching point O (symmetrical, relative to the slit) is
  A)
  \[\frac{2\pi }{{{n}_{1}}{{\lambda }_{1}}}({{n}_{3}}-{{n}_{2}})t\]       done clear
  B)
  \[\frac{2\pi }{{{\lambda }_{1}}}({{n}_{3}}-{{n}_{2}})t\] done clear
  C)
  \[\frac{2\pi {{n}_{1}}}{{{n}_{2}}{{\lambda }_{1}}}\left( \frac{{{n}_{3}}}{{{n}_{2}}}-1 \right)t\] done clear
  D)
         \[\frac{2\pi {{n}_{1}}}{{{\lambda }_{1}}}({{n}_{3}}-{{n}_{2}})t\] done clear
  View Solution play_arrow

• question_answer52)
  A beam of light consisting of two wavelength \[6500\,\overset{o}{\mathop{A}}\,\] and \[5200\,\overset{o}{\mathop{A}}\,\]is used to obtain interference fringes in a young's double slit experiment. The distance between the slits is 2.0 mm and the distance between the plane of the slits and the screen is 120 cm. What is the least distance from the central maximum where the bright fringes due to both the wave length coincide?
  A)
  0.156 cm done clear
  B)
  0.152 cm done clear
  C)
  0.17 cm  done clear
  D)
  0.16 cm done clear
  View Solution play_arrow

• question_answer53)
  A double slit, \[{{S}_{1}}-{{S}_{2}}\]is illuminated by a light source S emitting light of wavelength\[\lambda \]. The slits are separated by a distance d. A plane mirror is placed at a distance D in front of the slits and a screen is placed at a distance 2D behind the slits. The screen receives light reflected only by the plane mirror. The fringe-width of the interference pattern on the screen is       
  A)
  \[\frac{D\lambda }{d}\] done clear
  B)
  \[\frac{2D\lambda }{d}\] done clear
  C)
  \[\frac{3D\lambda }{d}\] done clear
  D)
  \[\frac{4D\lambda }{d}\] done clear
  View Solution play_arrow

• question_answer54)
  In a Young's double slit experiment, the fringes are displaced by a distance x when a glass plate of refractive index 1.5 is introduced in the path of one of the beams. When this plate is replaced by another plate of same thickness, the shift of fringes is \[(3/2)x\]. The refractive index of second plate is
  A)
  1.75   done clear
  B)
  1.50   done clear
  C)
  1.25   done clear
  D)
  1.00 done clear
  View Solution play_arrow

• question_answer55)
  A certain region of a soap bubble reflects red light of wavelength \[\lambda =650nm\]. What is the minimum thickness that this region of the soap bubble could have? Take the index of reflection of the soap film to be 1.41.     
  A)
  \[1.2\times {{10}^{-7}}m\] done clear
  B)
  \[650\times {{10}^{-9}}m\] done clear
  C)
  \[120\times {{10}^{7}}m\] done clear
  D)
  \[650\times {{10}^{5}}m\] done clear
  View Solution play_arrow

• question_answer56)
  In figure, Young's double slit experiment Q is the position of the first bright fringe on the right side of O. P is the\[{{11}^{th}}\]fringe on the other side, as measured from Q. If\[\lambda =6000\overset{o}{\mathop{A}}\,\], then \[{{S}_{1}}B\]will be equal to                             
  A)
  \[6\times {{10}^{-6}}m\] done clear
  B)
  \[6.6\times {{10}^{-6}}m\] done clear
  C)
  \[3.318\times {{10}^{-7}}m\] done clear
  D)
  \[3.144\times {{10}^{-7}}m\] done clear
  View Solution play_arrow

• question_answer57)
  The intensity of a point source of light, S, placed at a distance d in front of a screen A, is \[{{I}_{0}}\] at the center of the screen. Find the light intensity at the center of the screen if a completely reflecting plane mirror M is placed at a distance d behind the source, as shown in figure.
  A)
  \[\frac{27\,{{I}_{0}}}{9}\]         done clear
  B)
  \[\frac{25\,{{I}_{0}}}{9}\] done clear
  C)
  \[\frac{17\,{{I}_{0}}}{9}\]         done clear
  D)
  \[\frac{10\,{{I}_{0}}}{9}\] done clear
  View Solution play_arrow

• question_answer58)
  In Young's double slit interference experiment, the slit widths are in the ratio 1 : 25. Then the ratio of intensity at the maxima and minima in the interference pattern is
  A)
  3 : 2  done clear
  B)
  1 : 25 done clear
  C)
  9 : 4  done clear
  D)
  1 : 5 done clear
  View Solution play_arrow

• question_answer59)
  The maximum number of possible interference maxima for slit separation equal to\[1.8\lambda \], where\[\lambda \] is the wavelength of light used, in a Young's double slit experiment is
  A)
  zero       done clear
  B)
  3     done clear
  C)
  infinite   done clear
  D)
  5 done clear
  View Solution play_arrow

• question_answer60)
  In a Young's double slit experiment, if the incident light consists of two wavelengths \[{{\lambda }_{1}}\]and \[{{\lambda }_{2}}\], the slit separation is d, and the distance between the slit and the screen is D, the maxima due to the two wavelengths will coincide at a distance from the central maxima, given by:
  A)
  \[\frac{{{\lambda }_{1}}{{\lambda }_{2}}}{2\,Dd}\]      done clear
  B)
  \[({{\lambda }_{1}}-{{\lambda }_{2}}).\frac{2d}{D}\] done clear
  C)
  LCM of \[{{\lambda }_{1}}.\frac{D}{d}\] and \[{{\lambda }_{2}}.\frac{D}{d}\] done clear
  D)
  HCF of \[\frac{{{\lambda }_{1}}D}{d}\] and \[\frac{{{\lambda }_{2}}D}{d}\] done clear
  View Solution play_arrow

• question_answer61)
  Consider the YDSE arrangement shown in figure. If \[d=10\lambda \] then position of \[{{8}^{th}}\] maxima is
  A)
  \[y=\frac{D}{10}\] done clear
  B)
  \[y=\frac{D}{3}\] done clear
  C)
  \[y=\frac{4}{5}D\] done clear
  D)
  \[y=\frac{4D}{3}\] done clear
  View Solution play_arrow

• question_answer62)
  Two rectangular glass plates are in contact at one edge while the other edges are separated by a space of some suitable thickness so as to form a low angle wedge. The spacer is placed parallel to the line of contact and is at a distance of 10 cm from it. When viewed normally in light of wavelength 5500 A, a series of evenly spaced dark bands 0.5 mm apart are seen. The thickness of the spacer is :   
  A)
  0.0425cm done clear
  B)
  0.0036cm done clear
  C)
  0.0055cm done clear
  D)
  0.0254cm done clear
  View Solution play_arrow

• question_answer63)
  At two points P and Q on screen in Young's double slit experiment, waves from slits \[{{S}_{1}}\]and \[{{S}_{2}}\] have a path difference of 0 and\[\frac{\lambda }{4}\], respectively. The ratio of intensities at P and Q will be:
  A)
  \[2:1\] done clear
  B)
  \[\sqrt{2}:1\] done clear
  C)
  \[4:1\] done clear
  D)
  \[3:2\] done clear
  View Solution play_arrow

• question_answer64)
  In a Young's double slit experiment, the two slits act as coherent sources of wave of equal amplitude A and wavelength X. In another experiment with the same arrangement the two slits are made to act as incoherent sources of waves of same amplitude and wavelength. If the intensity at the middle point of the screen in the first case is\[{{I}_{1}}\]and in the second case is\[{{I}_{2}}\], then the ratio\[\frac{{{I}_{1}}}{{{I}_{2}}}\]is
  A)
  2  done clear
  B)
  1      done clear
  C)
  0.5 done clear
  D)
  4 done clear
  View Solution play_arrow

• question_answer65)
  On a hot summer night, the refractive index of air is smallest near the ground and increases with height from the ground. When a light beam is directed horizontally, the Huygens' principle leads us to conclude that as it travels, the light beam :
  A)
  bends downwards done clear
  B)
  bends upwards done clear
  C)
  becomes narrower done clear
  D)
  goes horizontally without any deflection done clear
  View Solution play_arrow

• question_answer66)
  Assuming human pupil to have a radius of 0.25 cm and a comfortable viewing distance of 25 cm, the minimum separation between two objects that human eye can resolve at 500 nm wavelength is:
  A)
  \[100\mu m\] done clear
  B)
  \[~300\mu m\] done clear
  C)
  \[1\mu m\] done clear
  D)
  \[~30\mu m\] done clear
  View Solution play_arrow

• question_answer67)
  In Young's double slit experiment, one of the slit is wider than other, so that amplitude of the light from one slit is double of that other slit. If\[{{I}_{m}}\]be the maximum intensity, the resultant intensity I when they interfere at phase difference\[\phi \] is given by
  A)
  \[\frac{{{I}_{m}}}{9}(4+5\cos \phi )\]    done clear
  B)
  \[\frac{{{I}_{m}}}{3}(1+2{{\cos }^{2}}\frac{\phi }{2})\] done clear
  C)
  \[\frac{{{I}_{m}}}{5}(1+4{{\cos }^{2}}\frac{\phi }{2})\] done clear
  D)
         \[\frac{{{I}_{m}}}{9}(1+8{{\cos }^{2}}\frac{\phi }{2})\] done clear
  View Solution play_arrow

• question_answer68)
  Abeam of unpolarised light of intensity L is passed through a polaroidAand then through another polaroid B which is oriented so that its principal plane makes an angle of \[45{}^\circ \] relative to that of A. The intensity of the emergent light is
  A)
  \[{{I}_{0}}\] done clear
  B)
  \[{{I}_{0}}/2\]   done clear
  C)
  \[{{I}_{0}}/4\] done clear
  D)
  \[{{I}_{0}}/8\] done clear
  View Solution play_arrow

• question_answer69)
  Two beams, A and B, of plane polarized light with mutually perpendicular planes of polarization are seen through a polaroid. From the position when the beam A has maximum intensity (and beam B has zero intensity), a rotation of polaroid through \[30{}^\circ \] makes the two beams appear equally bright. If the initial intensities of the two beams are\[{{I}_{A}}\]and \[{{I}_{B}}\] respectively, then\[\frac{{{I}_{A}}}{{{I}_{B}}}\]equals
  A)
  3          done clear
  B)
  \[\frac{3}{2}\]               done clear
  C)
  1          done clear
  D)
  \[\frac{1}{3}\] done clear
  View Solution play_arrow

• question_answer70)
  In a Young's double slit experiment, slits are separated by 0.5 mm, and the screen is placed 150 cm away. A beam of light consisting of two wavelengths, 650 nm and 520 nm, is used to obtain interference fringes on the screen. The least distance from the common central maximum to the point where the bright fringes due to both the wavelengths coincide is :
  A)
  9.75 mm done clear
  B)
  15.6 mm done clear
  C)
  1.56 mm done clear
  D)
  7.8 mm done clear
  View Solution play_arrow

• question_answer71)
  The box of a pin hole camera, of length L, has a hole of radius a. It is assumed that when the hole is illuminated by a parallel beam of light of wavelength\[\lambda \]the spread of the spot (obtained on the opposite wall of the camera) is the sum of its geometrical spread and the spread due to diffraction. The spot would then have its minimum size\[(say\,\,{{b}_{\min }})\]when : 
  A)
  \[a=\sqrt{\lambda L}\] and \[{{b}_{\min }}\,=\sqrt{4\lambda L}\] done clear
  B)
  \[a=\frac{{{\lambda }^{2}}}{L}\] and \[{{b}_{\min \,}}=\sqrt{4\lambda L}\] done clear
  C)
  \[a=\frac{{{\lambda }^{2}}}{L}\] and  \[{{b}_{\min }}=\left( \frac{2{{\lambda }^{2}}}{L} \right)\] done clear
  D)
  \[a=\sqrt{\lambda 1}\] and \[{{b}_{\min }}=\left( \frac{2{{\lambda }^{2}}}{L} \right)\]      done clear
  View Solution play_arrow

• question_answer72)
  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 polarioid whose polarization axis makes an angle 9 with the polarization axis of first polaroid, is placed between these polaroids then the intensity of light emerging from the last polaroid will be
  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
  View Solution play_arrow

• question_answer73)
  The width of the diffraction band varies
  A)
  inversely as the wavelength done clear
  B)
  directly as the width of the slit done clear
  C)
  directly as the distance between the slit and the screen done clear
  D)
  inversely as the size of the source from which the slit is illuminated done clear
  View Solution play_arrow

• question_answer74)
  The first diffraction minimum due to the single slit diffraction is seen at \[9=30{}^\circ \] for a light of wavelength 5000 A falling perpendicularly on the slit. The width of the slit is
  A)
  \[2.5\times {{10}^{-5}}cm\]    done clear
  B)
         \[1.25\times {{10}^{-5}}cm\] done clear
  C)
  \[10\times {{10}^{-5}}cm\]       done clear
  D)
  \[5\times {{10}^{-5}}cm\] done clear
  View Solution play_arrow

• question_answer75)
  An unpolarised beam of intensity\[{{I}_{0}}\]is incident on a pair of nicols making an angle of \[60{}^\circ \] with each other. The intensity of light emerging from the pair is
  A)
  \[{{I}_{0}}\]   done clear
  B)
  \[{{I}_{0}}/2\]   done clear
  C)
  \[{{I}_{0}}/4\]  done clear
  D)
  \[{{I}_{0}}/8\] done clear
  View Solution play_arrow

• question_answer76)
  The angle substanded by the first diffraction minimum for a point source viewed in the hydrogen line at 1420 MHz with a radio telescope having an aperture of 25 m is:  
  A)
  \[0.8{}^\circ \] done clear
  B)
  \[0.64{}^\circ \] done clear
  C)
  \[1.2{}^\circ ~\] done clear
  D)
  \[2.2{}^\circ \] done clear
  View Solution play_arrow

• question_answer77)
  The angle of incidence at which reflected light is totally polarized for reflection from air to glass (refractive index n) is
  A)
  \[{{\tan }^{-1}}(1/n)\] done clear
  B)
  \[{{\sin }^{-1}}(1/n)\] done clear
  C)
  \[{{\sin }^{-1}}(n)\] done clear
  D)
  \[{{\tan }^{-1}}(n)\] done clear
  View Solution play_arrow

• question_answer78)
  A polaroid is placed at \[45{}^\circ \] to an incoming light of intensity I. Now the intensity of light after polarisation would be
  A)
  I     done clear
  B)
         \[I/2\]  done clear
  C)
  \[I/\sqrt{2}\]       done clear
  D)
  zero done clear
  View Solution play_arrow

• question_answer79)
  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)
  \[30{}^\circ \]               done clear
  B)
  \[45{}^\circ \]   done clear
  C)
  \[~60{}^\circ \]            done clear
  D)
  \[75{}^\circ \] done clear
  View Solution play_arrow

• question_answer80)
  When the diffraction pattern from a certain slit illuminated with laser light\[(\lambda =6330\,{{A}^{o}})\] is projected on a screen 150 cm from the slit, the second minima on each side are separated by 8 cm. This tells us that:               
  A)
  the slit is approximately 0.005 cm wide done clear
  B)
  the slit is approximately 0.05 cm wide done clear
  C)
  \[a/\lambda \], is approximately 7.5 (a is the slit width) done clear
  D)
  \[a/\lambda \]is approximately 750 done clear
  View Solution play_arrow

• question_answer81)
  When an unpolarized light of intensity\[{{I}_{0}}\]incident on a polarizing sheet, the intensity of the light which does not get transmitted is
  A)
  \[\frac{1}{4}{{I}_{0}}\] done clear
  B)
  \[\frac{1}{2}{{I}_{0}}\]  done clear
  C)
  \[{{I}_{0}}\]    done clear
  D)
  zero done clear
  View Solution play_arrow

• question_answer82)
  The angle of polarisation for any medium is \[60{}^\circ \]The critical angle for this is
  A)
  \[{{\sin }^{-1}}\frac{1}{\sqrt{3}}\] done clear
  B)
  \[{{\cos }^{-1}}\sqrt{3}\] done clear
  C)
  \[{{\sin }^{-1}}\sqrt{3}\] done clear
  D)
  \[{{\tan }^{-1}}\sqrt{3}\] done clear
  View Solution play_arrow

• question_answer83)
  If \[{{I}_{0}}\] is me intensity of the principal maximum in the single slit diffraction pattern, then what will be its intensity when the slit width is doubled?
  A)
  \[4{{I}_{0}}\]   done clear
  B)
  \[2{{I}_{0}}\]   done clear
  C)
  \[\frac{{{I}_{0}}}{2}\] done clear
  D)
  \[{{I}_{0}}\] done clear
  View Solution play_arrow

• question_answer84)
  Two polaroids have their polarizing directions parallel so that the intensity of a transmitted light is maximum. The angle through which either polaroid must be turned if the intensity is to drop by one-half is               
  A)
  \[135{}^\circ \] done clear
  B)
  \[90{}^\circ \]    done clear
  C)
  \[120{}^\circ \] done clear
  D)
  \[180{}^\circ \] done clear
  View Solution play_arrow

• question_answer85)
  In an experiment of single slit diffraction pattern, first minimum for red light coincides with first maximum of some other wavelength. If wavelength of red light is 6600 A, then wavelength of first maximum will be:
  A)
  \[~3300\,\overset{o}{\mathop{A}}\,\] done clear
  B)
  \[4400\,\overset{o}{\mathop{A}}\,\] done clear
  C)
  \[5500\overset{o}{\mathop{\,A}}\,\] done clear
  D)
  \[6600\,\overset{o}{\mathop{A}}\,\] done clear
  View Solution play_arrow

• question_answer86)
  A mixture of polarised and unpolarised light is incident on a polariser. As the polariser is rotated through\[360{}^\circ \], it is found that the minimum and the maximum of the transmitted intensity is in the ratio 1: q. The ratio of intensities of polarized to unpolarised light in the incident beam is
  A)
  \[\frac{1}{2}(q-1):1\] done clear
  B)
  \[1:\frac{1}{2}(q-1)\] done clear
  C)
  \[\frac{1}{2}q:1\] done clear
  D)
  \[1:\frac{1}{2}q\] done clear
  View Solution play_arrow

• question_answer87)
  The intensity of the central maximum in Young's double-slit experiment is 41. The intensity at the first minimum is zero and the distance between two consecutive maxima is w. The distance from the central maximum to the position where the intensity falls to I is
  A)
  \[\frac{2}{3}w\]  done clear
  B)
  \[\frac{1}{4}w\]  done clear
  C)
  \[\frac{1}{2}w\] done clear
  D)
  \[\frac{1}{3}w\] done clear
  View Solution play_arrow

• question_answer88)
  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)
  \[38.2{{A}^{o}}\] done clear
  B)
  \[68.32{{A}^{o}}\] done clear
  C)
  \[5892.{{A}^{o}}\] done clear
  D)
  \[528.32{{A}^{o}}\] done clear
  View Solution play_arrow

• question_answer89)
  In a Young's double slit experiment 10 fringes are observed in a given segment of the screen when light of wavelength 500.0 nm is used. When the experiment is performed in a medium of refractive index 1.2, the number of fringes observed in the same segment remains 10. The wavelength of light used in this case is
  A)
  400.0 nm done clear
  B)
  417.7nm done clear
  C)
  500.0nm done clear
  D)
  600.0nm done clear
  View Solution play_arrow

• question_answer90)
  A narrow monochromatic beam of light of intensity I is incident on a glass plate as shown in figure. Another identical glass plate is kept close to the first one   and parallel to it. Each glass plate reflects 25 per cent of the light incident on it and transmits the remaining. Find the ratio of the minimum and the maximum intensities in the interference pattern formed by the two beams obtained after one reflection at each plate.
  A)
  \[1:30\] done clear
  B)
  \[1:49\]         done clear
  C)
  \[1:51\] done clear
  D)
  \[1:73\]         done clear
  View Solution play_arrow

• question_answer91)
  In YDSE a light containing two wavelengths 500 nm and 700 nm are used. Find the minimum distance where maxima of two wavelengths coincide. Given \[D/d={{10}^{3}}\], where D is the distance between the slits and the screen and d is the distance between the slits.
  A)
  1.2 m done clear
  B)
  3.5 mm done clear
  C)
  2.8 cm done clear
  D)
  8.1 mm done clear
  View Solution play_arrow

• question_answer92)
  In a double slit experiment slits \[{{S}_{1}}\], \[{{S}_{2}}\] is illuminated by a coherent light of wavelength\[\lambda \]. The slits are separated by a distance d. The experimental set up is modified by using plane mirrors as shown in figure. Find the fringe width of interference pattern on the screen.              
  A)
  \[\frac{(3{{D}_{1}}+2{{D}_{2}})\lambda }{d}\] done clear
  B)
  \[\frac{(2{{D}_{1}}+3{{D}_{2}})\lambda }{d}\] done clear
  C)
  \[\frac{(3{{D}_{2}}-3{{D}_{1}})\lambda }{d}\] done clear
  D)
  \[\frac{(3{{D}_{1}}-2{{D}_{2}})\lambda }{2d}\] done clear
  View Solution play_arrow

• question_answer93)
  A radio transmitting station operating at a frequency of 120 MHz has two identical antennas that radiate in phase. Antenna B is 9 m to the right of antenna A. Consider point P at a horizontal distance x to the right of antenna A as shown in Fig. The value of x and order for which the constructive interference will occur at point P is                
  A)
  \[x=14.95m,\,\,n=2\] done clear
  B)
  \[x=5.6m,\,\,\,n=2\] done clear
  C)
  \[x=1.65m,\,\,\,\,n=3\] done clear
  D)
  \[x=0,\,\,\,n=3.6\] done clear
  View Solution play_arrow

• question_answer94)
  If one of the slits of a standard Young's double slit experiment is covered by a thin parallel sided glass slab so that it transmits only one half the light intensity of the other, then-
  A)
  the fringe pattern will get shifted towards the covered slit done clear
  B)
  the fringe pattern will get shifted away from the covered slit done clear
  C)
  the bright fringes will become more bright and the dark ones will become less bright done clear
  D)
  the fringe width will changed done clear
  View Solution play_arrow

• question_answer95)
  If screen is shifted in x direction away from source, then which of the following is incorrect?
  A)
  Central maxima is shifted along x-axis done clear
  B)
  Position of all maximas except the central maxima change done clear
  C)
  Fringe width remains constant done clear
  D)
  Angular width changes due to shifting done clear
  View Solution play_arrow

• question_answer96)
  A light wave of wavelength\[{{\lambda }_{0}}\]propagates from point A to point B. We introduce in its path a glass plate of refractive index n and thickness l. The introduction of the plate alters the phase of the plate at B by an angle\[\phi \]. If \[\lambda \] is the wavelength of lights on emerging from the plate, then
  A)
  \[\Delta \phi =0\] done clear
  B)
         \[\Delta \phi =\frac{2\pi l}{{{\lambda }_{0}}}\] done clear
  C)
  \[\Delta \phi =2\pi {{\ln }^{2}}\left( \frac{1}{\lambda }-\frac{1}{{{\lambda }_{0}}} \right)\] done clear
  D)
  \[\Delta \phi =\frac{2\pi l}{{{\lambda }_{0}}}(n-1)\] done clear
  View Solution play_arrow

• question_answer97)
  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 done clear
  B)
  its wavelength decreases, frequency remain same done clear
  C)
  its wavelength increases, frequency remain same done clear
  D)
  bothe remains contant done clear
  View Solution play_arrow

• question_answer98)
  (distance between slit and screen D = 12cm and distance between slits d = 5cm.) then the wavelength of the radiation used can be-
  A)
  3/4 cm              done clear
  B)
  4 cm, 5cm done clear
  C)
  2/3 cm, 2/5 cm     done clear
  D)
  4/3 cm, 5/3 cm done clear
  View Solution play_arrow

• question_answer99)
  In Young's double-slit experiment, let A and B be the two slits. A thin film of thickness t and refractive index [i is placed in front of A. Let\[\beta =frings\] width. Then the central maxima will shift
  A)
  toward A done clear
  B)
  toward B done clear
  C)
  by \[t(\mu -1)\frac{\beta }{\lambda }\]   done clear
  D)
  by \[\mu t\frac{\beta }{\lambda }\] done clear
  View Solution play_arrow

• question_answer100)
  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 \[3\,{{I}_{0}}\] done clear
  B)
  O is zero done clear
  C)
  a point 1 m  below O is \[4\,{{I}_{0}}\] done clear
  D)
  a point on the screen 1 m below O is zero done clear
  View Solution play_arrow