10th Class Science Light - Reflection and Refraction Question Bank

done Light Total Questions - 269

• question_answer1)
  The Huygens' theory of light fails to explain
  A)
   photoelectric effect   done clear
  B)
   interference done clear
  C)
   diffraction done clear
  D)
   reflection and refraction Not Available done clear
  View Solution play_arrow

• question_answer2)
  Wave nature of light was proposed by
  A)
   Huygens            done clear
  B)
          Young done clear
  C)
   Fresnel                done clear
  D)
          Maxwell Not Available done clear
  View Solution play_arrow

• question_answer3)
  Which of the following phenomenon cannot be explained by the Huygens' wave theory?
  A)
   Reflection done clear
  B)
   Refraction done clear
  C)
   Formation of spectrum   done clear
  D)
   Diffraction Not Available done clear
  View Solution play_arrow

• question_answer4)
  A ray of light from air is incident in water; then which property of light will not change in water?
  A)
   Velocity           done clear
  B)
          Frequency   done clear
  C)
   Amplitude        done clear
  D)
          Colour Not Available done clear
  View Solution play_arrow

• question_answer5)
  If a mirror has a focal length of+ 15 cm, then it is a
  A)
   convex mirror   done clear
  B)
   concave mirror done clear
  C)
   plane mirror done clear
  D)
   none of these Not Available done clear
  View Solution play_arrow

• question_answer6)
  The rectilinear propagation of light in a medium is due to
  A)
   its large wavelength done clear
  B)
   its high frequency   done clear
  C)
   its large velocity done clear
  D)
  refractive index of the medium Not Available done clear
  View Solution play_arrow

• question_answer7)
  A plane mirror reflecting a ray of incident light is rotated in the plane of incidence through an angle \[\theta \], then
  A)
   reflected ray does not rotate done clear
  B)
   reflected ray rotates through an angle \[\theta \] done clear
  C)
   reflected ray rotates through an angle \[2\theta \]   done clear
  D)
   incident ray is fixed Not Available done clear
  View Solution play_arrow

• question_answer8)
  If two mirrors are kept at \[60{}^\circ \] to each other and a body is placed in the middle, then total number of images formed is
  A)
   three                    done clear
  B)
   four done clear
  C)
   five                         done clear
  D)
          six Not Available done clear
  View Solution play_arrow

• question_answer9)
  When a convergent beam of light is incident on a plane mirror, then image formed is
  A)
   upright and real done clear
  B)
   upright and virtual done clear
  C)
   inverted and virtual   done clear
  D)
   inverted and real Not Available done clear
  View Solution play_arrow

• question_answer10)
  The term reflection refers to the bending of light
  A)
   rays when these strike a mirror   done clear
  B)
   rays when these enter a different medium done clear
  C)
   around a sharp edge done clear
  D)
   around the boundary of a narrow aperture Not Available done clear
  View Solution play_arrow

• question_answer11)
  Number of images observable between two parallel mirrors is
  A)
   2 done clear
  B)
   4 done clear
  C)
   6 done clear
  D)
   infinite   done clear
  View Solution play_arrow

• question_answer12)
  A reflecting telescope utilises
  A)
   a convex mirror done clear
  B)
   a concave mirror   done clear
  C)
   a prism done clear
  D)
   a plano-concave lens done clear
  View Solution play_arrow

• question_answer13)
  What should be the angle between the two mirrors so that, whatever may be the angle of incidence, the incident ray and the reflected ray from the two mirrors will he parallel to each other?
  A)
  \[45{}^\circ \] done clear
  B)
         \[75{}^\circ \] done clear
  C)
  \[90{}^\circ \]   done clear
  D)
         \[120{}^\circ \] done clear
  View Solution play_arrow

• question_answer14)
  For a spherical mirror, the graph of\[~\frac{1}{\upsilon }\text{v/s}\frac{1}{u}\]is
  A)
  .                                               done clear
  B)
                done clear
  C)
                                                    done clear
  D)
         done clear
  View Solution play_arrow

• question_answer15)
  When a monochromatic beam of light passes from a denser medium to a rarer medium, then
  A)
   its velocity increases   done clear
  B)
   its velocity decreases done clear
  C)
   its frequency decreases done clear
  D)
   its wavelength decreases done clear
  View Solution play_arrow

• question_answer16)
  When a ray of light enters a glass slab from air, then
  A)
   its wavelength decreases   done clear
  B)
   its wavelength increases done clear
  C)
   its frequency increases done clear
  D)
   neither wavelength nor frequency changes done clear
  View Solution play_arrow

• question_answer17)
  If a mirror has a focal length of-20 cm, then it is a
  A)
   convex mirror done clear
  B)
   concave mirror   done clear
  C)
   plane mirror done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer18)
  In case of a virtual and erect image, the magnification of a mirror is
  A)
   positive             done clear
  B)
          negative done clear
  C)
   unity                     done clear
  D)
          infinity done clear
  View Solution play_arrow

• question_answer19)
  In case of a real and inverted image, the magnification of a mirror is
  A)
   positive           done clear
  B)
          negative done clear
  C)
   zero                      done clear
  D)
          infinity   done clear
  View Solution play_arrow

• question_answer20)
  When light enters from air to water, then its frequency
  A)
   increases and speed decreases done clear
  B)
   is same but the wavelength is smaller in water than in air   done clear
  C)
   is same but the wavelength in water is greater than in air done clear
  D)
   decreases and wavelength is smaller in water than in air done clear
  View Solution play_arrow

• question_answer21)
  Stars, twinkle due to
  A)
   refraction           done clear
  B)
          reflection done clear
  C)
   scattering         done clear
  D)
          polarisation of light done clear
  View Solution play_arrow

• question_answer22)
  A cut diamond sparkles because of its
  A)
   high refractive index   done clear
  B)
   hardness done clear
  C)
   emission of light by the diamond done clear
  D)
   absorption of light by the diamond done clear
  View Solution play_arrow

• question_answer23)
  For an object at infinity, a concave mirror produces an image at its focus which is
  A)
   enlarged done clear
  B)
   virtual done clear
  C)
   erect done clear
  D)
   real, inverted and diminished   done clear
  View Solution play_arrow

• question_answer24)
  The mirror used in automobiles to see the rear view is
  A)
   concave           done clear
  B)
          convex   done clear
  C)
   plane                    done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer25)
  A mirror having a very wide field of view must be
  A)
   concave          done clear
  B)
          convex   done clear
  C)
   plane                    done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer26)
  When a monochromatic light wave train passes from air to glass across a plane surface of separation of the two media
  A)
   its direction must change done clear
  B)
   its frequency must change done clear
  C)
   its wavelength increases done clear
  D)
   its wavelength decreases   done clear
  View Solution play_arrow

• question_answer27)
  The mirror used in search lights is
  A)
   concave             done clear
  B)
          convex done clear
  C)
   plane                    done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer28)
  A real image, equal in size to the object, is obtained when the object is placed at the centre of curvature in front of a
  A)
   concave mirror     done clear
  B)
         plane mirror done clear
  C)
   convex mirror    done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer29)
  Shaving mirrors are
  A)
   convex mirrors done clear
  B)
   concave mirrors   done clear
  C)
   plane mirrors done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer30)
  The magnification produced by a concave mirror
  A)
   is always more than one done clear
  B)
   is always less than one done clear
  C)
   is always equal to one done clear
  D)
   may be less than or greater than one   done clear
  View Solution play_arrow

• question_answer31)
  The relation between u, u and r is
  A)
   \[r=\frac{2u\upsilon }{u+\upsilon }\]       done clear
  B)
          \[r=\frac{2}{u+\upsilon }\] done clear
  C)
   \[r=\frac{2(u+\upsilon )}{(u\upsilon )}\]               done clear
  D)
          none of these           done clear
  View Solution play_arrow

• question_answer32)
  Which is the wrong statement out of the following?
  A)
   A concave mirror can give a virtual image   done clear
  B)
   A convex mirror can give a virtual image done clear
  C)
   A convex lens can give a virtual image done clear
  D)
   None of these done clear
  View Solution play_arrow

• question_answer33)
  A mirage occurs because
  A)
   the hot ground acts like a mirror done clear
  B)
   the refractive index of atmosphere decreases with height done clear
  C)
   the refractive index of atmosphere increases with height   done clear
  D)
   the refractive index remains constant with height done clear
  View Solution play_arrow

• question_answer34)
  Total internal reflection can occur when light passes from
  A)
   a rarer to denser medium done clear
  B)
   a denser to a rarer medium   done clear
  C)
   one medium to another of equal refractive index done clear
  D)
   one medium to another of equal absorption coefficient done clear
  View Solution play_arrow

• question_answer35)
  The refractive indices of water, glass and diamond are 1.33,1.50 and 2.40 respectively. The refractive index of diamond relative to water and of glass relative to diamond respectively are nearly
  A)
   1.80,0.625           done clear
  B)
          0554,0.625 done clear
  C)
   1.80, 1.6           done clear
  D)
          0.554,1.6 done clear
  View Solution play_arrow

• question_answer36)
  Two media are separated by a plane surface. Speed of light in one medium is \[\text{2}.0\text{ }\times \text{ 1}{{0}^{\text{1}0}}\text{ cm}/\text{sec}\]and in the other the speed it is\[\text{2}.\text{4 }\times \text{ 1}{{0}^{\text{1}0}}\text{ cm}/\text{sec}\]. The critical angle for a ray going from the first medium into the second will be
  A)
   \[{{\sin }^{-1}}\frac{1}{2}\]         done clear
  B)
          \[{{\sin }^{-1}}\left( \frac{5}{6} \right)\]   done clear
  C)
   \[{{\sin }^{-1}}\frac{5}{12}\]       done clear
  D)
          \[{{\sin }^{-1}}\left( \frac{1}{\sqrt{2}} \right)\] done clear
  View Solution play_arrow

• question_answer37)
  A light wave enters from first medium into second medium. Its velocity in second medium is double of that in first medium. For the phenomenon of total internal reflection to take place, the angle of incidence must be greater than a certain value. This value is
  A)
  \[90{}^\circ \] done clear
  B)
         \[60{}^\circ \] done clear
  C)
  \[45{}^\circ \] done clear
  D)
         \[30{}^\circ \]   done clear
  View Solution play_arrow

• question_answer38)
  The unit of magnification is
  A)
   m                           done clear
  B)
          \[{{\text{m}}^{\text{2}}}\] done clear
  C)
  \[{{\text{m}}^{-\text{1}}}\]                         done clear
  D)
          None of these   done clear
  View Solution play_arrow

• question_answer39)
  The laws of reflection are true for
  A)
   the plane mirror only done clear
  B)
   the concave mirror only done clear
  C)
   the convex mirror only done clear
  D)
   all reflecting surfaces   done clear
  View Solution play_arrow

• question_answer40)
  A virtual image is one which
  A)
   can be taken on a screen done clear
  B)
   cannot be taken on a screen   done clear
  C)
   sometimes can be and sometimes cannot be taken on a screen done clear
  D)
   is formed only by a concave mirror done clear
  View Solution play_arrow

• question_answer41)
  The line joining the pole and the centre of curvature of a mirror is called the
  A)
   aperture          done clear
  B)
          principal section done clear
  C)
   principal axis        done clear
  D)
          pole done clear
  View Solution play_arrow

• question_answer42)
  An inverted image can be seen in a convex mirror
  A)
   under no circumstances   done clear
  B)
   when the object is very far from the mirror done clear
  C)
   when the object is at a distance equal to the radius of curvature of the mirror done clear
  D)
   when the distance of the object from the mirror is equal to the focal length of the mirror done clear
  View Solution play_arrow

• question_answer43)
  Ratio of the size of the image to the size of the object is known as
  A)
   focal plane       done clear
  B)
          transformation ratio done clear
  C)
   efficiency        done clear
  D)
   none of these   done clear
  View Solution play_arrow

• question_answer44)
  In order to get a diminished virtual image, the object can be placed anywhere in front of a
  A)
   concave mirror   done clear
  B)
         plane mirror done clear
  C)
   convex mirror      done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer45)
  The mirror used by dentists to concentrate light on the tooth to be examined is a
  A)
   concave mirror   done clear
  B)
   plane or concave mirror done clear
  C)
   convex mirror done clear
  D)
   plane mirror done clear
  View Solution play_arrow

• question_answer46)
  When an object is at infinity from a concave mirror, then image formed is
  A)
   at the focus         done clear
  B)
          virtual and erect done clear
  C)
   highly enlarged   done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer47)
  When the object is at focus of a concave mirror, the image is formed at
  A)
   focus              done clear
  B)
          centre of curvature done clear
  C)
   within focus         done clear
  D)
          infinity   done clear
  View Solution play_arrow

• question_answer48)
  A ray of light falls on a transparent glass slab of refractive index 1.52. If the reflected ray and refracted ray are mutually perpendicular, then the angle of incidence is
  A)
  \[58{}^\circ \text{ }15'\] done clear
  B)
         \[57{}^\circ \text{ }19'\] done clear
  C)
  \[58{}^\circ \text{ }19'\] done clear
  D)
         \[57{}^\circ \text{ }12'\] done clear
  View Solution play_arrow

• question_answer49)
  An air bubble in a glass slab \[\left( \text{m }=\text{ 1}.\text{5} \right)\] is 6 cm deep as viewed from one face and 4 cm deep as wed from the other face. The thickness of the glass slab is
  A)
   10 cm                   done clear
  B)
          15 cm   done clear
  C)
   6.67cm                 done clear
  D)
          11.67cm done clear
  View Solution play_arrow

• question_answer50)
  Which of the following ray diagrams is not correct?
  A)
  done clear
  B)
    done clear
  C)
  done clear
  D)
    done clear
  View Solution play_arrow

• question_answer51)
  When an object is kept within the focus of a concave mirror, an enlarged image is formed behind the mirror. The nature of the image is a
  A)
   real done clear
  B)
   inverted done clear
  C)
   virtual and inverted done clear
  D)
   virtual and erect   done clear
  View Solution play_arrow

• question_answer52)
  A substance through which light can pass is called a/an
  A)
   optical medium   done clear
  B)
          transparent body done clear
  C)
   opaque body      done clear
  D)
          translucent body done clear
  View Solution play_arrow

• question_answer53)
  A body which allows most of the light to pass  through it is called a
  A)
   transparent body              done clear
  B)
   opaque body done clear
  C)
   translucent body done clear
  D)
         none of these done clear
  View Solution play_arrow

• question_answer54)
  Refractive index of medium B with respect to medium A is equal to
  A)
   the reciprocal of the refractive index of medium B with respect to medium A done clear
  B)
   the reciprocal of the refractive index of medium A with respect to medium B   done clear
  C)
   the refractive index of medium A with respect to medium B done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer55)
  Path along which light travels in a homogenous medium is called
  A)
   beam of light done clear
  B)
          ray of light   done clear
  C)
   pencil of light     done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer56)
  A thin layer of water is transparent but a very thick layer of water is
  A)
   translucent         done clear
  B)
          opaque done clear
  C)
   most transparent            done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer57)
  Amount of light reflected depends upon
  A)
   nature of material of the object done clear
  B)
   nature of the surface done clear
  C)
   smoothness of the surface done clear
  D)
   all of these   done clear
  View Solution play_arrow

• question_answer58)
  Air is not visible because it
  A)
   is nearly a perfectly transparent substance done clear
  B)
   neither absorbs nor reflects light done clear
  C)
   transmits whole of light done clear
  D)
   all of these   done clear
  View Solution play_arrow

• question_answer59)
  Refractive index of a given piece of transparent  quartz is greatest for
  A)
   red light           done clear
  B)
          violet light   done clear
  C)
   green light        done clear
  D)
          yellow light done clear
  View Solution play_arrow

• question_answer60)
  Ratio of the refractive index of red light to blue light in air is
  A)
   less than unity   done clear
  B)
   equal to unity done clear
  C)
   greater than unity done clear
  D)
   less as well as greater than unity depending upon the experimental arrangement done clear
  View Solution play_arrow

• question_answer61)
  A completely transparent material will be invisible in vacuum when the refractive index p, is
  A)
   unity                       done clear
  B)
          more than unity done clear
  C)
   less than unity    done clear
  D)
          equal to 1.33 done clear
  View Solution play_arrow

• question_answer62)
  A real image is formed when two or more
  A)
   reflected rays meet   done clear
  B)
   refracted rays meet done clear
  C)
   reflected rays appear to meet done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer63)
  Image of our face in a plane mirror is
  A)
   real                       done clear
  B)
          magnified done clear
  C)
   diminished       done clear
  D)
          none of these   done clear
  View Solution play_arrow

• question_answer64)
  Nature of the image formed by a plane mirror is
  A)
   virtual and erect done clear
  B)
   of the same size as the object done clear
  C)
   laterally inverted done clear
  D)
   all of these   done clear
  View Solution play_arrow

• question_answer65)
  Sideways reversal of the image by plane mirror is called
  A)
   lateral inversion   done clear
  B)
          parallex done clear
  C)
   optical illusion     done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer66)
  Middle point of the mirror is called
  A)
   pole   done clear
  B)
   centre of sphere done clear
  C)
   centre of curvature done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer67)
  A light wave has a frequency of \[\text{4}\times \text{1}{{0}^{\text{14}}}\text{ Hz}\]and wavelength of\[\text{5}\times \text{1}{{0}^{-\text{7}}}\text{ m}\]. The refractive index of the medium in which it is travelling is
  A)
    1.20                done clear
  B)
          2.40 done clear
  C)
   1.50                   done clear
  D)
          1.75 done clear
  View Solution play_arrow

• question_answer68)
  A beam of monochromatic blue light of wavelength 4200A in air travels in water (retractive index = \[\frac{4}{3}\]). Its wavelength in water will be
  A)
   \[\text{28}00\overset{\circ }{\mathop{\text{A}}}\,\] done clear
  B)
   \[3150\overset{\circ }{\mathop{\text{A}}}\,\]   done clear
  C)
   \[4000\overset{\circ }{\mathop{\text{A}}}\,\] done clear
  D)
   \[5600\overset{\circ }{\mathop{\text{A}}}\,\] done clear
  View Solution play_arrow

• question_answer69)
  A fish in a lake at a depth h sees the outside world through a circular aperture at the surface. The radius of the aperture is
  A)
   \[\frac{\mu }{\sqrt{{{h}^{2}}-1}}\]           done clear
  B)
          \[\mu \sqrt{{{h}^{2}}-1}\] done clear
  C)
   \[h\sqrt{{{\mu }^{2}}-1}\]           done clear
  D)
          \[\frac{h}{\sqrt{{{\mu }^{2}}-1}}\]   done clear
  View Solution play_arrow

• question_answer70)
  A container of depth H is filled with two immiscible transparent liquids of refraelive indices \[{{\mu }_{1}}\], and \[{{\mu }_{2}}\] respectively. The depth of each type of liquid is\[\frac{H}{2}\] . When viewed from above, the apparent depth of the vessel is
  A)
   \[\frac{H}{2}\left[ \frac{1}{{{\mu }_{1}}}+\frac{{{\mu }_{1}}}{{{\mu }_{2}}} \right]\]           done clear
  B)
   \[\frac{H}{2}\left[ \frac{1}{{{\mu }_{1}}}+\frac{1}{{{\mu }_{2}}} \right]\] done clear
  C)
   \[H\left[ \frac{1}{{{\mu }_{1}}}+\frac{{{\mu }_{1}}}{{{\mu }_{2}}} \right]\] done clear
  D)
          \[\frac{H}{2}\left[ \frac{{{\mu }_{1}}{{\mu }_{2}}}{{{\mu }_{1}}+{{\mu }_{2}}} \right]\] done clear
  View Solution play_arrow

• question_answer71)
  Refer to the mirror formula, \[\frac{1}{v}+\frac{1}{u}=\frac{1}{f}\] , where the symbols have their usual meanings, which of the following graphs correctly depicts this variation?
  A)
                                                     done clear
  B)
         done clear
  C)
                                                       done clear
  D)
   none of these   done clear
  View Solution play_arrow

• question_answer72)
  Which of the following correctly depicts the graphical variation in case of a convex mirror?
  A)
                                                    done clear
  B)
         done clear
  C)
                                    done clear
  D)
         done clear
  View Solution play_arrow

• question_answer73)
  A plane mirror gives a real image when the incident beam is
  A)
   wide done clear
  B)
   narrow done clear
  C)
   convergent   done clear
  D)
   divergent done clear
  View Solution play_arrow

• question_answer74)
  Two points such that each focus for the rays proceeding from the other, are called
  A)
   centres of curvature done clear
  B)
   conjugate foci   done clear
  C)
   converging foci done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer75)
  The linear magnification for a mirror is the ratio of the size of the image to the size of the object, and is denoted by m. Then m is equal to (symbols have their usual meanings)
  A)
   \[\frac{uf}{u-f}\]             done clear
  B)
          \[\frac{u\,f}{u-f}\] done clear
  C)
   \[\frac{\,f}{u+f}\]           done clear
  D)
          none of these   done clear
  View Solution play_arrow

• question_answer76)
  In Question 75 above, m is equal to
  A)
   \[\frac{u+\,f}{f}\]           done clear
  B)
          \[\frac{uf}{u-f}\] done clear
  C)
   \[\frac{f}{u+f}\]               done clear
  D)
          none of these   done clear
  View Solution play_arrow

• question_answer77)
  In case of a concave mirror, when the object is situated at the principal focus, then image formed is
  A)
   real and inverted done clear
  B)
         of infinite size done clear
  C)
   lies at infinity     done clear
  D)
          all of these   done clear
  View Solution play_arrow

• question_answer78)
  The angle of crown glass (\[\mu =1.52\]) prism \[{{5}^{\circ }}\] What should be the angle of flint glass  (\[\text{ }\mu =\text{ 1}.\text{63}\]) prism so that the two prisms together may be used in a direct vision spectroscope?
  A)
  \[-\text{2}.\text{14}{}^\circ \]                    done clear
  B)
          \[+\text{2}.\text{14}{}^\circ \] done clear
  C)
  \[-\text{4}.\text{12}{}^\circ \]                      done clear
  D)
          \[+\text{4}.\text{12}{}^\circ \] done clear
  View Solution play_arrow

• question_answer79)
  One cannot see through fog because
  A)
   fog absorbs light done clear
  B)
   light is scattered by the droplets in a fog   done clear
  C)
   light suffers total reflection at the droplet in a fog done clear
  D)
   the refractive index of fog is infinity done clear
  View Solution play_arrow

• question_answer80)
  In case of a concave mirror, when the object lies between the pole and the principal focus, then image formed is
  A)
   virtual            done clear
  B)
          erect done clear
  C)
   magnified         done clear
  D)
          all of these   done clear
  View Solution play_arrow

• question_answer81)
  The rays parallel and close to the principal axis are called
  A)
   converging rays  done clear
  B)
         divergent rays done clear
  C)
   coherent rays     done clear
  D)
          paraxial rays   done clear
  View Solution play_arrow

• question_answer82)
  The angle which the periphery of the spherical mirror subtends at the centre of curvature is called
  A)
   aperture          done clear
  B)
          glancing angle   done clear
  C)
   critical angle      done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer83)
  Critical angle of light passing from glass to air is minimum for
  A)
   red                        done clear
  B)
          green done clear
  C)
   yellow             done clear
  D)
          violet   done clear
  View Solution play_arrow

• question_answer84)
  It is possible to observe total internal reflection when a ray travels from
  A)
   air into water     done clear
  B)
          air into glass done clear
  C)
   water into glass  done clear
  D)
         glass into water   done clear
  View Solution play_arrow

• question_answer85)
  A rectangular block of glass is placed on a mark made on the surface of the table and it is viewed from the vertical position of eye. If refractive index of glass be \[\mu \] and its thickness d, then the mark will appear to be raised up by
  A)
   \[\frac{(\mu +1)}{\mu }\]            done clear
  B)
          \[\frac{(\mu -1)d}{\mu }\]            done clear
  C)
   \[\frac{(\mu -1)d}{\mu d}\]       done clear
  D)
          \[\frac{(\mu -1)\mu }{d}\] done clear
  View Solution play_arrow

• question_answer86)
  A lens form a sharp image on a screen. On inserting a parallel-sides slab of glass between die lens and the screen it is found necessary to move the screen a distance d away from the lens in order for the image to be again sharply focused. If the refractive index of glass relative to air is u, then the thickness of the slab is
  A)
   \[\frac{d}{\mu }\]                           done clear
  B)
          \[\frac{\mu }{d}\] done clear
  C)
   \[\frac{\mu d}{\mu -1}\]               done clear
  D)
          \[\frac{(\mu -1)d}{\mu }\] done clear
  View Solution play_arrow

• question_answer87)
  As the object is brought nearer to the vertex of a mirror, it is found that the image also moves towards the vertex. The mirror must be
  A)
   convex                  done clear
  B)
   concave done clear
  C)
   concave or convex         done clear
  D)
   paraboloid done clear
  View Solution play_arrow

• question_answer88)
  The principle of successive reflections of light at inclined mirrors is used in
  A)
   periscope   done clear
  B)
         telescope done clear
  C)
   microscope        done clear
  D)
          kaleidoscope   done clear
  View Solution play_arrow

• question_answer89)
  A ray of light from denser medium strikes a rarer medium at angle of incidence \[i\]. The reflected and refracted rays make an angle of \[90{}^\circ \] with each other. The angle of reflection and refraction are r and \[r'.\] The critical angle is
  A)
  \[\text{si}{{\text{n}}^{-\text{1}}}\text{ }\left( \text{tan r} \right)\]        done clear
  B)
          \[{{\sin }^{-1}}(\tan i)\]   done clear
  C)
  \[\text{si}{{\text{n}}^{-1}}\text{ }\left( \text{tan r}' \right)\]      done clear
  D)
         \[{{\sin }^{-1}}(\tan (i+r)\] done clear
  View Solution play_arrow

• question_answer90)
  If a ray of light incident on a plane mirror is such that it makes an angle of \[30{}^\circ \] with the mirror, then the angle of reflection is
  A)
  \[30{}^\circ \] done clear
  B)
         \[4.5{}^\circ \] done clear
  C)
  \[55{}^\circ \] done clear
  D)
         \[60{}^\circ \]   done clear
  View Solution play_arrow

• question_answer91)
  In Question 90 above, the angle made by the reflected ray with the mirror is
  A)
  \[30{}^\circ \]   done clear
  B)
  \[45{}^\circ \] done clear
  C)
  \[55{}^\circ \] done clear
  D)
         \[60{}^\circ \] done clear
  View Solution play_arrow

• question_answer92)
  Ray optics holds good when characteristic dimensions are
  A)
   of the same order as the wavelength of light   done clear
  B)
   much smaller than the wavelength of light done clear
  C)
   of the order of one millimeter done clear
  D)
   much larger than the wavelength of light done clear
  View Solution play_arrow

• question_answer93)
  To an observer on the earth the stars appear to twinkle. This can be described to
  A)
   the fact that stars do not emit light continuously done clear
  B)
   frequency absorption of star light by their own atmosphere done clear
  C)
   frequency absorption of slur light by the earth's atmosphere done clear
  D)
   refractive index fluctuates in the earth?s atmosphere   done clear
  View Solution play_arrow

• question_answer94)
  A diver in a swimming pool wants to signal his distress to a person lying on the edge of the pool by flashing his waterproof flash light
  A)
   he must direct the beam vertically upwards done clear
  B)
   he has to direct the beam horizontally done clear
  C)
   he has to direct the beam at an angle to the vertical which is slightly less than the critical angle of incidence for total internal reflection   done clear
  D)
   he has to direct the beam at an angle to the vertical which is slightly more than the critical angle of incidence for total internal reflection done clear
  View Solution play_arrow

• question_answer95)
  The distance between the extreme points on the periphery of the mirror is called
  A)
   focal length         done clear
  B)
           radius of curvature                 done clear
  C)
   principal section   done clear
  D)
                    none of these done clear
  View Solution play_arrow

• question_answer96)
  The centre of curvature of a _____ mirror is in front of it.
  A)
   convex           done clear
  B)
          concave   done clear
  C)
   convex or concave         done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer97)
  The centre of curvature of a _____ mirror is behind it.
  A)
   convex   done clear
  B)
   concave done clear
  C)
   convex or concave done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer98)
  A concave lens of focal length\[f\]produces an image equal to \[\frac{1}{n}\] of the size of the object, the distance of the object from the lens is
  A)
   \[(n-1)F\]             done clear
  B)
          \[(n+1)F\] done clear
  C)
   \[\left( \frac{n-1}{n} \right)F\]  done clear
  D)
          \[\left( \frac{n+1}{n} \right)F\] done clear
  View Solution play_arrow

• question_answer99)
  Which of the following correctly depicts the reflection of a ray of light on a spherical mirror?
  A)
    done clear
  B)
    done clear
  C)
      done clear
  D)
    done clear
  View Solution play_arrow

• question_answer100)
  A ray, emerging from a point on the object, passing through the centre of curvature C strikes the mirror normally i.e. al \[90{}^\circ \]. Then, the angle of incidence is equal to
  A)
   \[{{0}^{^{\circ }}}\]                           done clear
  B)
          \[{{45}^{^{\circ }}}\] done clear
  C)
   \[{{90}^{^{\circ }}}\]                       done clear
  D)
          \[{{180}^{^{\circ }}}\] done clear
  View Solution play_arrow

• question_answer101)
  A double convex lens of focal length 15 cm is to be used as a magnifying glass. In order to produce an erect image which is 3 times magnified, the distance between the object and the lens should be
  A)
  \[+\text{ 5 cm}\]          done clear
  B)
                          \[+\text{ 1}0\text{ cm}\]   done clear
  C)
  \[+\text{ 15 cm}\]          done clear
  D)
         \[~\text{2}0\text{ cm}\] done clear
  View Solution play_arrow

• question_answer102)
  A planoconvex lens, when silvered in the plane side behaves like a concave mirror of focal length 30 cm. However, when silvered on the convex side it behaves like a concave mirror of focal length 10 cm. Then the refrective index of its, material will be
  A)
   3.0                   done clear
  B)
          2.0 done clear
  C)
   2.5                   done clear
  D)
          1.5   done clear
  View Solution play_arrow

• question_answer103)
  In Q. No. 102, the true radius of curvature of the spherical surface of plano-convex lens is
  A)
   30 cm                     done clear
  B)
          60 cm done clear
  C)
   10 cm                   done clear
  D)
          20 cm done clear
  View Solution play_arrow

• question_answer104)
   Which of the following mirror is used to concentrate light on a given spot?
  A)
   Concave mirror    done clear
  B)
         Convex mirror done clear
  C)
   Plane mirror     done clear
  D)
          None of these done clear
  View Solution play_arrow

• question_answer105)
  The concave mirrors are used in
  A)
   reflecting telescopes     done clear
  B)
   magic-lanterns done clear
  C)
   cinema projectors          done clear
  D)
   all of these   done clear
  View Solution play_arrow

• question_answer106)
  The focal length of a lens of glass \[{{(}_{a}}{{\mu }_{g}}=3/2)\] air is 10 cm. The focal length of the lens when it is immersed in water \[{{(}_{a}}{{\mu }_{W}}=4/3)\] will be
  A)
   40cm                      done clear
  B)
          50cm done clear
  C)
   60 cm                   done clear
  D)
          80 cm done clear
  View Solution play_arrow

• question_answer107)
  Light is a form of_______ that we can detect with our_______.
  A)
   energy, ears       done clear
  B)
          corpuscles, eyes done clear
  C)
   energy, eyes        done clear
  D)
          sensation, skin done clear
  View Solution play_arrow

• question_answer108)
  Unit of power of a lens is
  A)
   metre             done clear
  B)
          dyne done clear
  C)
   dioptre                  done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer109)
  Least distance of distinct-vision for a normal person is about
  A)
   1 m                        done clear
  B)
          0.5 m done clear
  C)
   0.25m                     done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer110)
  Focal length of a lens is 50 cm. Its power would be
  A)
   50 dioptres        done clear
  B)
          2 dioptres   done clear
  C)
   20 dioptres        done clear
  D)
          None of these done clear
  View Solution play_arrow

• question_answer111)
  Unit of refractive index is
  A)
   metre             done clear
  B)
          degree done clear
  C)
   dioptre            done clear
  D)
          it has no units   done clear
  View Solution play_arrow

• question_answer112)
  A simple magnifying glass consists of a
  A)
   concave lens done clear
  B)
   convex lens of large focal length done clear
  C)
   convex lens of small focal length   done clear
  D)
   plane mirror only done clear
  View Solution play_arrow

• question_answer113)
  Figures [a], [b], [c] and [d] respectively correspond to [a] the short-sighted eye, the correction of long-sight, the long-sighted eye and the correction of short-sight [b] the short-sighted eye, the correction of short- sight, the long-sighted eye and the correction of long-sight [c] the long-sighted eye, correction of short-sight, the short-sighted eye and the correction of long-sight [d] none of these
  A)
                                                    done clear
  B)
    done clear
  C)
                                                                 done clear
  D)
  done clear
  View Solution play_arrow

• question_answer114)
  Screen behind the eye lens is called the
  A)
   iris done clear
  B)
   ciliary muscle done clear
  C)
   retina   done clear
  D)
   pupil done clear
  View Solution play_arrow

• question_answer115)
  Cornea is a transparent spherical structure which
  A)
   reflects light                      done clear
  B)
   scatters light done clear
  C)
   refracts light                        done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer116)
  Image on the retina remains for
  A)
   20 s                done clear
  B)
          10 s done clear
  C)
   \[\frac{1}{10}s\]                done clear
  D)
          \[\frac{1}{20}s\]   done clear
  View Solution play_arrow

• question_answer117)
  When a plane mirror is roated through an angle \[\theta \], then the reflected ray rotates through an angle \[2\theta \]; then the size of the image
  A)
   is halved done clear
  B)
   is doubled done clear
  C)
   remains unchanged   done clear
  D)
   is quadrupled done clear
  View Solution play_arrow

• question_answer118)
  A plane mirror produces a magnification of
  A)
   ? 1 done clear
  B)
   +1   done clear
  C)
   zero done clear
  D)
   between \[0\,\,and\,+\infty \] done clear
  View Solution play_arrow

• question_answer119)
  A double convex lens of focal length 6 cm is made of glass of refractive index 1.5. The radius of curvature of one surface which is double that of the other surface will be
  A)
   3 cm                                      done clear
  B)
   9 cm   done clear
  C)
   12 cm                   done clear
  D)
          24 cm done clear
  View Solution play_arrow

• question_answer120)
  Middle vascular coat that darkens the eye chamber and prevents refraction by absorbing the light rays is
  A)
   choroid             done clear
  B)
          sclera done clear
  C)
   retina                   done clear
  D)
          cornea done clear
  View Solution play_arrow

• question_answer121)
  Amount of light entering the eye is controlled by the
  A)
   iris                         done clear
  B)
          cornea done clear
  C)
   pupil                       done clear
  D)
          crystalline lens done clear
  View Solution play_arrow

• question_answer122)
  Eye lens is a
  A)
   transparent double-convex lens   done clear
  B)
   transparent double-concave lens done clear
  C)
   transparent concavo-convex lens done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer123)
  Eye lens contains a watery liquid called the
  A)
   aqueous humour   done clear
  B)
         peroxide done clear
  C)
   vitreous humour done clear
  D)
         none of these done clear
  View Solution play_arrow

• question_answer124)
  Long-sightedness is caused by the eyeball being too short. It can be corrected by the use of a
  A)
   convergent lens   done clear
  B)
          plane mirror done clear
  C)
   divergent lens    done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer125)
  Astigmatism occurs when the cornea does not have a truly spherical shape. This defect can be curved by the use of a
  A)
   concave lens      done clear
  B)
          cylindrical lens done clear
  C)
   convex lens         done clear
  D)
          plano-convex lens done clear
  View Solution play_arrow

• question_answer126)
  When an object moves towards a convex lens, the size of the image
  A)
   decreases done clear
  B)
   increases   done clear
  C)
   first decreases then increases done clear
  D)
   remains the same done clear
  View Solution play_arrow

• question_answer127)
  When an object approaches a convex lens from infinity, then image formed by it shifts
  A)
   away from the lens   done clear
  B)
   towards the lens done clear
  C)
   first away and then towards the lens done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer128)
  Amount of light entering in the eye is controlled by the
  A)
   pupil                       done clear
  B)
          iris done clear
  C)
   cornea            done clear
  D)
          eye lens done clear
  View Solution play_arrow

• question_answer129)
  Liquid contained in the eye lens is called
  A)
   peroxide          done clear
  B)
          aqueous humour   done clear
  C)
   vitreous humour done clear
  D)
         none of these done clear
  View Solution play_arrow

• question_answer130)
  Which of the following correctly represent graphical relation between angle of incidence (\[i\]) and angle of reflection (r)?
  A)
                                                  done clear
  B)
         done clear
  C)
                                                  done clear
  D)
           done clear
  View Solution play_arrow

• question_answer131)
  The bending of light as it passes from one medium into another is commonly known as
  A)
   reflection         done clear
  B)
          refraction   done clear
  C)
   scattering        done clear
  D)
          dispersion done clear
  View Solution play_arrow

• question_answer132)
  Which of the following correctly represents the graphical variation between very small angles of incidence (i) and refraction (r)?
  A)
                                                  done clear
  B)
         done clear
  C)
                                                           done clear
  D)
         done clear
  View Solution play_arrow

• question_answer133)
  Which of the following graphical variation produces a straight line?
  A)
   Angle of incidence versus angle of reflection   done clear
  B)
   Angle of incidence versus angle of refraction done clear
  C)
   Sine of angle of incidence versus sine of am of refraction done clear
  D)
   All of these done clear
  View Solution play_arrow

• question_answer134)
  A ray of light travelling inside a rectangular glass. block of refractive index \[\sqrt{2}\] is incident on the glass-air interface at an angle of incidence of \[{{45}^{\circ }}\]The refractive index of air is one. Under the these conditions the ray will
  A)
   emerge into the air without any deviation done clear
  B)
   be reflected back into glass done clear
  C)
   be absorbed done clear
  D)
   emerge into the air with an angle of refraction equal to \[90{}^\circ \]   done clear
  View Solution play_arrow

• question_answer135)
  A straight line graph is obtained by plotting sine of angle of incidence versus sine of angle of refraction. The slope of this graph represents
  A)
   velocity of light   done clear
  B)
         refractive index   done clear
  C)
   gravitational      done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer136)
  Which of the following quantity does not have any unit?
  A)
   Velocity of light  done clear
  B)
         Light year done clear
  C)
   Magnification       done clear
  D)
          Power of a lens done clear
  View Solution play_arrow

• question_answer137)
  When light travels from one medium into another, it suffers
  A)
   reflection          done clear
  B)
          refraction   done clear
  C)
   dispersion         done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer138)
  When a convex lens of focal length 10 cm is placed in contact with a concave lens, the combination has a power of + 5 diopter. The power of combination, when the lenses are separated by 10 cm in air, will be
  A)
   \[+10D\]               done clear
  B)
          \[+20D\] done clear
  C)
   \[-5D\]                 done clear
  D)
          \[-30D\] done clear
  View Solution play_arrow

• question_answer139)
  The distance of the sun form the earth is \[~\text{1}.\text{5}\times \text{1}{{0}^{\text{11}}}\] m and its diameter is \[\text{1}.\text{4}0\text{ }\times \text{ 1}{{0}^{\text{9}}}\] m The diameter of the image of the sun formed by a lens of focal length 1m is nearly
  A)
  \[\text{1 }\times \text{ 1}0.\text{4 m}\]          done clear
  B)
          \[\text{1 }\times \text{ 1}0.\text{3 m}\] done clear
  C)
  \[\text{1 }\times \text{ 1}0.\text{2 m}\]            done clear
  D)
          \[\text{1}00\text{ m}\] done clear
  View Solution play_arrow

• question_answer140)
  The refraction of light is commonly known as
  A)
   bending            done clear
  B)
          scattering done clear
  C)
   reflection         done clear
  D)
          interference done clear
  View Solution play_arrow

• question_answer141)
  When a ray of light passes from an optically less dense medium to a more dense medium, it
  A)
   Goes un deviated done clear
  B)
   bends towards the normal   done clear
  C)
   bends away from the normal done clear
  D)
   hone of these done clear
  View Solution play_arrow

• question_answer142)
  When a ray of light passes from an optically more dense medium to a less dense medium, it
  A)
   goes un deviated done clear
  B)
   bends towards the normal done clear
  C)
   bends away from the normal   done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer143)
  Which of the following shows the bending of light from water rarer (R) into denser  medium?
  A)
                                                                 done clear
  B)
    done clear
  C)
                                                  done clear
  D)
         done clear
  View Solution play_arrow

• question_answer144)
  Which of the following shows the bending of light from a denser [d] medium into a rarer (R) medium?
  A)
                                                  done clear
  B)
           done clear
  C)
                                                  done clear
  D)
         done clear
  View Solution play_arrow

• question_answer145)
  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
  View Solution play_arrow

• question_answer146)
  How will the image formed by a convex lens be affected, if the upper half of the lens is wrapped with a black paper?
  A)
   The size of the image is reduced to one half             done clear
  B)
   The upper half of the image will be absent                   done clear
  C)
   The brightness of the image is reduced   done clear
  D)
   There will be no effect done clear
  View Solution play_arrow

• question_answer147)
  A lens forms a real image on a screen placed at a distance 100 cm from the object if the lens is moved by 20 cm towards the screen, another image is formed on the screen. The focal length of the lens is
  A)
   6 cm                      done clear
  B)
          12 cm done clear
  C)
   18 cm                   done clear
  D)
          24 cm   done clear
  View Solution play_arrow

• question_answer148)
  How large will an image be formed of an artificial satellite, 5m in diameter, passing at an altitude of 500 km if it is photographed by a camera with a lens of focal length 10 cm.
  A)
  \[{{10}^{-2}}m\]             done clear
  B)
          \[{{10}^{-4}}m\] done clear
  C)
  \[{{10}^{-6}}m\]                 done clear
  D)
          \[5\times {{10}^{-6}}m\] done clear
  View Solution play_arrow

• question_answer149)
  Refractive index is
  A)
   directly proportional to wavelength of light done clear
  B)
   directly proportional to the square of wave- length of light done clear
  C)
   inversely proportional to wavelength of light done clear
  D)
   inversely proportional to the square of wave- length of light   done clear
  View Solution play_arrow

• question_answer150)
  A red piece of paper when illuminated by green light appears
  A)
   black                done clear
  B)
          blue done clear
  C)
   yellow             done clear
  D)
          green done clear
  View Solution play_arrow

• question_answer151)
  A direct vision spectroscope is constructed on the principle of
  A)
   deviation with dispersion done clear
  B)
   dispersion without deviation   done clear
  C)
   selective absorption done clear
  D)
   diffusion done clear
  View Solution play_arrow

• question_answer152)
  An object looks red when seen through a piece of red glass what is the actual colour of the object?
  A)
   Red only                               done clear
  B)
   White only done clear
  C)
   Red or green     done clear
  D)
          Black done clear
  View Solution play_arrow

• question_answer153)
  A glass slab is placed in the path of a beam of convergent light; the point of convergence of light
  A)
   moves towards the glass slab done clear
  B)
   moves away from the glass slab   done clear
  C)
   remains at the same point done clear
  D)
   undergoes a lateral shift done clear
  View Solution play_arrow

• question_answer154)
  Ratio of the sine of angle of incidence to the sine of angle of reflection is
  A)
   Snell's law done clear
  B)
  Brewster's angle done clear
  C)
  Refractive index done clear
  D)
   none of these   done clear
  View Solution play_arrow

• question_answer155)
  Ratio of the sine of angle of incidence to the sine of angle of refraction is
  A)
   Snell's law   done clear
  B)
   optical density done clear
  C)
   relative density done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer156)
  A swimming pool looks shallower than it really is, when seen by a person standing outside near it, because of the phenomenon of____ of light.
  A)
   refraction   done clear
  B)
   reflection done clear
  C)
   dispersion done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer157)
  In the primary rainbow, what is the order in which colours are observed?
  A)
   Violet innermost and red outermost   done clear
  B)
   Red innermost and violet outermost done clear
  C)
   Violet, blue, red, yellow done clear
  D)
   Haphazard done clear
  View Solution play_arrow

• question_answer158)
  A glass prism has refractive index 1.5 and the refracting angle is \[90{}^\circ \]. If a ray falls on it at an angle of incidence of \[30{}^\circ \], then angle of emergence will be
  A)
  \[60{}^\circ \] done clear
  B)
  \[30{}^\circ \] done clear
  C)
  \[45{}^\circ \] done clear
  D)
   The ray will not emerge out of his prism   done clear
  View Solution play_arrow

• question_answer159)
  Dispersive power of crown glass is (given\[{{\mu }_{v}}=1.523\,and\,{{\mu }_{R}}=1.5145\])
  A)
   1.6                         done clear
  B)
          0.16 done clear
  C)
   0.016                      done clear
  D)
   0.0016 done clear
  View Solution play_arrow

• question_answer160)
  The mirror formula is given by,\[\frac{1}{\upsilon }+\frac{1}{u}=\frac{1}{f}\] Where the symbols have their usual meanings. Then the lens formula is given by
  A)
   \[\frac{1}{\upsilon }+\frac{1}{u}=\frac{1}{f}\]    done clear
  B)
          \[\frac{1}{\upsilon }-\frac{1}{u}=\frac{1}{f}\]   done clear
  C)
   \[\frac{1}{\upsilon }+\frac{1}{u}=-\frac{1}{f}\]   done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer161)
  A convex lens is also called
  A)
   diverging lens     done clear
  B)
          converging lens   done clear
  C)
   cylindrical lens    done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer162)
  A lens is called a thin lens, if its overall thickness is
  A)
   small                       done clear
  B)
          large done clear
  C)
   infinitely large    done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer163)
  In optical instruments, the lenses are used to form images by
  A)
   reflection          done clear
  B)
          refraction   done clear
  C)
   dispersion         done clear
  D)
          scattering done clear
  View Solution play_arrow

• question_answer164)
  A lens which is thicker in the middle and thiner at the edges is called a
  A)
   convex lens   done clear
  B)
   concave lens done clear
  C)
   cylindrical lens done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer165)
  A lens which is thinner at the middle and thicker at the edges is called a
  A)
   convex lens       done clear
  B)
          concave lens   done clear
  C)
   cylindrical lens    done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer166)
  Principal axis is also called____ of the lens.
  A)
   optical axis          done clear
  B)
          \[x\]-axis done clear
  C)
   \[y\] -axis             done clear
  D)
          axis done clear
  View Solution play_arrow

• question_answer167)
  Power of a lens can't be measured in
  A)
   m                     done clear
  B)
          W done clear
  C)
   h.p.                       done clear
  D)
          all of these   done clear
  View Solution play_arrow

• question_answer168)
  I D is equal to
  A)
   1m                         done clear
  B)
          1 cm done clear
  C)
  \[\text{1 }{{\text{m}}^{-\text{1}}}\]                          done clear
  D)
          \[\text{1 c}{{\text{m}}^{-\text{1}}}\] done clear
  View Solution play_arrow

• question_answer169)
  If \[f\]is focal length of the lens, then the power of a lens is equal to
  A)
   \[\frac{100}{f(cm)}\]       done clear
  B)
          \[\frac{10}{f(cm)}\] done clear
  C)
   \[\frac{100}{f(cm)}\]     done clear
  D)
          \[\frac{1}{100f(cm)}\] done clear
  View Solution play_arrow

• question_answer170)
  Which of the following term is not associated with a lens?
  A)
   Aperture            done clear
  B)
          Focal length done clear
  C)
   Principal focus done clear
  D)
          Efficiency   done clear
  View Solution play_arrow

• question_answer171)
  Which of the following diagrams correctly represents the ray of light passing through the optical centre?
  A)
                                                    done clear
  B)
           done clear
  C)
                                    done clear
  D)
         done clear
  View Solution play_arrow

• question_answer172)
  A ray of light coming parallel to the principal axis after passing through a convex lens, passes through its
  A)
   optical centre       done clear
  B)
          focus done clear
  C)
   centre of curvature        done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer173)
  The focal length can be expressed in
  A)
   metre                    done clear
  B)
          diopter done clear
  C)
   watt                      done clear
  D)
          horse power done clear
  View Solution play_arrow

• question_answer174)
  The minimum deviation produced by a glass prism having an angle of \[60{}^\circ \] is \[30{}^\circ \]. If the velocity of light in vacuum is \[3\times 1010\text{ }cm/sec,\]then its velocity in glass will be
  A)
  \[~\text{2}.\text{12 }\times \text{ 1}{{0}^{\text{1}0}}\text{ cm}.{{\text{s}}^{-\text{1}}}\]             done clear
  B)
   \[\text{2}.\text{52 }\times \text{ 1}0\text{ cm}.{{\text{s}}^{-\text{1}}}\]   done clear
  C)
  \[2.21\times {{10}^{10}}cm.{{s}^{-1}}\] done clear
  D)
          \[\text{2}.\text{82 }\times \text{ 1}{{0}^{\text{1}0}}\text{ cm}.{{\text{s}}^{-\text{1}}}\] done clear
  View Solution play_arrow

• question_answer175)
  Where should an object be placed so that a real and inverted image of same size is obtained using a convex lens?
  A)
   Between the lens and its focus done clear
  B)
   At the focus done clear
  C)
   At twice the focal length done clear
  D)
   At infinity   done clear
  View Solution play_arrow

• question_answer176)
  The focal length of a lens \[-\text{ }0.\text{4 m}\]is. The lens is
  A)
   convex done clear
  B)
   concave done clear
  C)
   cylindrical   done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer177)
  The power of a lens is a measure of its degree of
  A)
   convergence only   done clear
  B)
   divergence only done clear
  C)
   convergence or divergence done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer178)
  The focal length of a lens is 0.1 m. Then the lens must be
  A)
   convex done clear
  B)
   concave done clear
  C)
   cylindrical   done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer179)
  Our eye lens is a
  A)
   convex lens       done clear
  B)
          concave lens done clear
  C)
   plano-convex lens            done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer180)
  Camera lenses are marked with
  A)
   dioptres          done clear
  B)
          metres done clear
  C)
   \[f\]- numbers         done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer181)
  Our eye lens is held in position by
  A)
   rods and cones   done clear
  B)
         iris and pupil done clear
  C)
   cilairy muscles      done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer182)
  Range of vision of a normal human eye is from
  A)
   100 m to 25 cm  done clear
  B)
          1 km to 25 cm done clear
  C)
   infinity to 25 m   done clear
  D)
          infinity to 25 cm   done clear
  View Solution play_arrow

• question_answer183)
  The Tar point5 of a normal human eye is
  A)
   25 cm                     done clear
  B)
          25 m done clear
  C)
   100m                    done clear
  D)
          at infinity done clear
  View Solution play_arrow

• question_answer184)
  The near point 7 of a normal human eye is
  A)
   25 m                     done clear
  B)
  17 m done clear
  C)
  1 m                        done clear
  D)
  25 cm   done clear
  View Solution play_arrow

• question_answer185)
  The time of exposure in a camera is controlled by a
  A)
   shutter                  done clear
  B)
   convex lens done clear
  C)
   bellows           done clear
  D)
          diaphragm done clear
  View Solution play_arrow

• question_answer186)
  The eye consists of an eye lens and a screen called
  A)
   retina                                     done clear
  B)
   iris done clear
  C)
   pupil                     done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer187)
  A combination of lenses made of different types of glass which do not produce spherical aberration are called
  A)
   converging lenses           done clear
  B)
   diverging lenses done clear
  C)
   anastigmatic lenses          done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer188)
  The process of getting a sharp and clear image of an object is called
  A)
   screening     done clear
  B)
          parallex done clear
  C)
   focussing         done clear
  D)
          none of these   done clear
  View Solution play_arrow

• question_answer189)
  A prism of refractive index \[\sqrt{2}\] has a refracting angle of \[60{}^\circ \]. At what angle a ray must be incident on it so that it suffers a minimum deviation?
  A)
  \[30{}^\circ \] done clear
  B)
         \[45{}^\circ \]   done clear
  C)
  \[60{}^\circ \] done clear
  D)
         \[90{}^\circ \] done clear
  View Solution play_arrow

• question_answer190)
  The power of a lens having a focal length of 1 cm is
  A)
   \[1\,D\]                                               done clear
  B)
   \[1\,0D\] done clear
  C)
   \[\frac{1}{10}D\]              done clear
  D)
          \[100\,D\]   done clear
  View Solution play_arrow

• question_answer191)
  A camera is an optical instrument which makes use of a
  A)
   convex lens         done clear
  B)
          concave lens done clear
  C)
   cylindrical lens    done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer192)
  Inability of a lens to bring all the rays coming from a point object to focus at one single point is called
  A)
   spherical aberration done clear
  B)
   parallex   done clear
  C)
   optical illusion done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer193)
  Spherical aberration can be minimised by        
  A)
   reducing the aperture of the lens done clear
  B)
   using speically made meniscus lens done clear
  C)
   combination of lenses made of different glasses   done clear
  D)
   all of these   done clear
  View Solution play_arrow

• question_answer194)
  Our eye makes use of the property of
  A)
   convex lens   done clear
  B)
   concave lens done clear
  C)
   cylindrical lens     done clear
  D)
                              none of these done clear
  View Solution play_arrow

• question_answer195)
  Most of the refraction of light takes place in the
  A)
   iris                         done clear
  B)
          cornea   done clear
  C)
   pupil                     done clear
  D)
          retina done clear
  View Solution play_arrow

• question_answer196)
  When the light is very bright, then     
  A)
   iris makes the pupil expand          done clear
  B)
   iris makes the pupil contract   done clear
  C)
   iris and the pupil remain as they are done clear
  D)
   none of these                       done clear
  View Solution play_arrow

• question_answer197)
  The magnifying power of an astronomical  telescope is 8, then the ratio of the focal length the objective to the focal length of the eye-piece is
  A)
   8                               done clear
  B)
          \[\frac{1}{8}\] done clear
  C)
   \[0.45\]               done clear
  D)
          None of these   done clear
  View Solution play_arrow

• question_answer198)
  Blue colour of sky is due to              
  A)
   scattering           done clear
  B)
          absorption       done clear
  C)
   reflection         done clear
  D)
          refraction        done clear
  View Solution play_arrow

• question_answer199)
  Colour of light is determined by its        
  A)
   wavelength          done clear
  B)
          frequency        done clear
  C)
   velocity            done clear
  D)
          amplitude        done clear
  View Solution play_arrow

• question_answer200)
  Long-sightedness is to hypermetropia as short sighteness is to                          
  A)
   myopia             done clear
  B)
          focusing         done clear
  C)
   astigmatism      done clear
  D)
         accommodation   done clear
  View Solution play_arrow

• question_answer201)
  Which of the following lens is used to minimise hypermetropia?                          
  A)
   convex lens          done clear
  B)
          concave lens      done clear
  C)
   cylindrical lens    done clear
  D)
          none of these     done clear
  View Solution play_arrow

• question_answer202)
  Which of the following lens is used to minimise a myopia?                                   
  A)
   convex lens       done clear
  B)
          concave lens         done clear
  C)
   cylindrical lens    done clear
  D)
          none of these      done clear
  View Solution play_arrow

• question_answer203)
  Human eye forms the image of an object at its
  A)
   cornea           done clear
  B)
          iris               done clear
  C)
   pupil                     done clear
  D)
          retina              done clear
  View Solution play_arrow

• question_answer204)
  Change in focal length of an eye-lens to focus the image of object at varying distances is done by the action of the                           
  A)
   pupil                done clear
  B)
          ciliary muscles      done clear
  C)
     retina             done clear
  D)
          blind spot           done clear
  View Solution play_arrow

• question_answer205)
  Total internal reflection takes place when light is incident                                   
  A)
   on a concave mirror                      done clear
  B)
   from air on a plane glass surface at a certain given angle                               done clear
  C)
   from air on a plane surface at any angle    done clear
  D)
   from inside a glass placed in water at a certain given angle                          done clear
  View Solution play_arrow

• question_answer206)
  When an object is placed between F and 2F in front of a convex lens, the image formed is
  A)
   real and inverted            done clear
  B)
   beyond 2F done clear
  C)
   magnified           done clear
  D)
          all of these   done clear
  View Solution play_arrow

• question_answer207)
  Magnifying power of an optical instrument is expressed in
  A)
   m                           done clear
  B)
          \[{{m}^{-1}}\] done clear
  C)
   D                            done clear
  D)
          it has no unit   done clear
  View Solution play_arrow

• question_answer208)
  A magnifying glass comprises a simple
  A)
   convex lens         done clear
  B)
          convex mirror done clear
  C)
   concave lens      done clear
  D)
          concave mirror done clear
  View Solution play_arrow

• question_answer209)
  The least distance of distinct vision for a normal person is
  A)
   1 m                          done clear
  B)
          25 cm done clear
  C)
   25 cm                   done clear
  D)
          None of these done clear
  View Solution play_arrow

• question_answer210)
  If the refractive indices of turpentine and water with respect to air are \[\text{1}\text{.8}\] and \[\text{1}\text{.3}\] respectively, then the refractive index of turpentine with respect to water will be
  A)
   \[\frac{5}{3}\]                     done clear
  B)
          \[\frac{18}{13}\] done clear
  C)
   \[2.8\]                   done clear
  D)
          \[\frac{5}{4}\] done clear
  View Solution play_arrow

• question_answer211)
   Total internal reflection in a non-magnetic medium occurs at\[\theta \,>\text{ 45}{}^\circ \]. In terms of velocity of light in vacuum [c], the velocity of light in this medium is
  A)
   \[c\]                      done clear
  B)
          \[0.707\,c\]   done clear
  C)
   \[\sqrt{\frac{3}{2}}\,c\]             done clear
  D)
          \[\frac{2}{3}\,c\] done clear
  View Solution play_arrow

• question_answer212)
  A point object is placed at a focus of a double concave lens. The image will be
  A)
   real and at infinity done clear
  B)
   virtual and at infinity done clear
  C)
   virtual and located between the object and lens   done clear
  D)
   none of the above done clear
  View Solution play_arrow

• question_answer213)
  Given figure represent three cases of a ray passing through a prism of refractive angle A. The case corresponding to minimum deviation is
  A)
   1                             done clear
  B)
          2 done clear
  C)
   3                               done clear
  D)
          None of these done clear
  View Solution play_arrow

• question_answer214)
  Indicate the colour of light which travels through glass with the minimum speed
  A)
   red                        done clear
  B)
          violet   done clear
  C)
   green                   done clear
  D)
          yellow done clear
  View Solution play_arrow

• question_answer215)
  A prism whose angular dispersion is \[30{}^\circ \] deviates light by \[60{}^\circ \]. The Dispersive Power of the Prims is
  A)
  \[0.\text{5}\]                    done clear
  B)
          \[0.0\text{5}\] done clear
  C)
  \[0.0\text{2}\]                done clear
  D)
          \[0.\text{2}\] done clear
  View Solution play_arrow

• question_answer216)
  At what angle does a diver seen the setting sun?
  A)
   At \[0{}^\circ \] to the horizontal done clear
  B)
   At \[90{}^\circ \] to the horizontal done clear
  C)
   At \[41{}^\circ \] to the horizontal   done clear
  D)
   At \[49{}^\circ \] to the horizontal done clear
  View Solution play_arrow

• question_answer217)
  Water is transparent to visible light. Still it is not possible to see object at a distance in fog which consists of fine drops of water suspended in air. This is so because
  A)
   fine drops of water are opaque to visible light done clear
  B)
   most of the light is scattered away, hence the apparent opacity   done clear
  C)
   fog affects our vision adversely done clear
  D)
   rays buffer total internal reflection and cannot reach the eye of the observer done clear
  View Solution play_arrow

• question_answer218)
  Rising and setting sun appears to be reddish because
  A)
   the sun is colder at sunrise or at sunset done clear
  B)
   diffraction sends red rays to the earth at these times done clear
  C)
   refraction is responsible for it done clear
  D)
   scattering due to dust particles and air molecules is responsible for it   done clear
  View Solution play_arrow

• question_answer219)
  A point source of light is placed at a distance of 2 f from a converging lens of focal length f. The intensity on the other side of the lens is maximum at a distance
  A)
   \[f\] done clear
  B)
   between \[f\] and 2\[f\] done clear
  C)
   2\[f\]   done clear
  D)
   more than 2 \[f\] done clear
  View Solution play_arrow

• question_answer220)
  A ray of light passes through an equilateral prism (refractive index = 1.5) such that the angle of incidence is equal to the angle of emergence and the latter is equal to 3/4 th the angle of the prism. The angle of deviation is
  A)
  \[20{}^\circ \] done clear
  B)
         \[39{}^\circ \] done clear
  C)
  \[45{}^\circ \] done clear
  D)
         \[30{}^\circ \]   done clear
  View Solution play_arrow

• question_answer221)
  A convex lens A of focal length 20 cm and a concave lens B of focal length 5 cm are kept along the same axis with a distance d between them. If a parellel beam of ligh falling on A leaves B as a parallel beam, then the distance d in cm will be
  A)
   25                          done clear
  B)
          15   done clear
  C)
   30                          done clear
  D)
          50 done clear
  View Solution play_arrow

• question_answer222)
  A glass slab of thickness 4 cm contains the same number of waves as 5 cm of water when both are traversed by the same monochromatic ligh. If the refractive index of water 4/3, what is the refractive index of glass?
  A)
   \[\frac{5}{3}\]                     done clear
  B)
          \[\frac{5}{4}\] done clear
  C)
   \[\frac{16}{15}\]                              done clear
  D)
          \[1.5\] done clear
  View Solution play_arrow

• question_answer223)
  To measure the refractive index of the material of a prism, we have to use
  A)
   the prism of any angle and light of any wavelength   done clear
  B)
   the prism with angle \[60{}^\circ \] and the white light only done clear
  C)
   the prism of angle \[60{}^\circ \] and sodium light only done clear
  D)
   the prism with angle \[60{}^\circ \] and any wavelength light done clear
  View Solution play_arrow

• question_answer224)
  A virtual image twice as big as the object is formed by a concaved lens when the object is 10 cm away from it. A real image twice as big as the object will be formed when it is placed at a distance from the lens
  A)
   40 cm                   done clear
  B)
          30 cm   done clear
  C)
   20cm                    done clear
  D)
          15cm done clear
  View Solution play_arrow

• question_answer225)
  When a lens is inserted between an object and a screen which are at a fixed distance apart, the size of the image in either 6 cm and 2/3 cm. The size of the object in cm is
  A)
   9                             done clear
  B)
          4 done clear
  C)
   3                             done clear
  D)
          2   done clear
  View Solution play_arrow

• question_answer226)
  A thin lens has focal length f, and its aperature has diameter d It forms an image of intensity \[I\] Now the central part of the aperature upto  diameter d/2 is blocked by an opaque paper. The focal length and image intensity will change to
  A)
   \[\frac{f}{2}and\frac{I}{2}\]        done clear
  B)
          \[f\,and\frac{I}{4}\] done clear
  C)
   \[\frac{3f}{4}\,and\frac{I}{2}\]  done clear
  D)
          \[f\,and\frac{3I}{4}\]   done clear
  View Solution play_arrow

• question_answer227)
  Photographs of the ground are taken from an aircraft flying at an altitude of 2000 m by a camera with a lens of focal length 50 cm. The size of the film in the camera is 18 cm x 18 cm. The area of the ground that can be photographed by the camera is
  A)
   \[720m\times 720m\]   done clear
  B)
   \[720m\times 720m\] done clear
  C)
   \[360cm\times 360cm\] done clear
  D)
   none of these done clear
  View Solution play_arrow

• question_answer228)
  A convergent beam of light converges to a point 20 cm behind a concave lens on the principal axis. An inverted image of the same size is formed Then the focal lenght of the lens is
  A)
   20 cm                   done clear
  B)
          10 cm             done clear
  C)
   40 cm                   done clear
  D)
          30 cm           done clear
  View Solution play_arrow

• question_answer229)
  What is the minimum and maximum distance between the convex lens and the object for the magnification of a real image to be greater than 1?
  A)
   O and \[f\] done clear
  B)
   \[f\] and 2\[f\]   done clear
  C)
   \[f\] and \[\infty \] done clear
  D)
   2\[f\]and \[\infty \] done clear
  View Solution play_arrow

• question_answer230)
  Light takes 8 minuts 20 seconds to reach from sun on the earth. If the whole atmosphere is filled with water, the light will take the time  \[({{\mu }_{w}}=4\text{/}3)\]
  A)
   8 minutes 20 seconds done clear
  B)
   8 minutes done clear
  C)
   6 minutes 11 seconds done clear
  D)
   11 minutes 6 seconds   done clear
  View Solution play_arrow

• question_answer231)
  We wish to make a piano concaved lens of focal length 16 cm from glass having refractive index\[\text{1}\text{.5}\]. It is to be used in air. What would be the radius of curvature of the curved surface?
  A)
   8cm   done clear
  B)
   12cm done clear
  C)
   16 cm done clear
  D)
   24cm done clear
  View Solution play_arrow

• question_answer232)
  A luminous object is placed 20 cms from the surface of a convex mirror and a plane mirror is get so that the virtual images formed in the two mirrors coincide. If the plane mirror is at a distance of 12 cms from the object, then the focal length of the convex mirror is
  A)
   10 cm                   done clear
  B)
          5 cm   done clear
  C)
   20 cm                   done clear
  D)
          40 cm done clear
  View Solution play_arrow

• question_answer233)
  A ray of light is incident normally on an isosceles right angled prism of glass of refractive index 1-5 as shown in the figure. Which of the following figures correctly depicts the path of the ray as it passes through the prism?
  A)
                                                                done clear
  B)
  done clear
  C)
                                                           done clear
  D)
  done clear
  View Solution play_arrow

• question_answer234)
  A glass prism of refractive index \[\text{1}\text{.5}\] is immersed in water of refractive index 4/3. A ray of light incident normally on face AB is totally reflected at face AC if
  A)
   \[\sin \theta >\frac{8}{9}\]                           done clear
  B)
   \[\sin \theta <\frac{8}{9}\] done clear
  C)
   \[\sin \theta =\frac{1}{\sqrt{2}}\]            done clear
  D)
          None of these done clear
  View Solution play_arrow

• question_answer235)
  A man who is \[\text{1}\text{.4}0\] m tall stands in front of a mirror and can just see himself from head to top. Assuming that his eyes are \[0.\text{14}\] m below the top of his head, the minimum height of the mirror is
  A)
  \[\text{1}\text{.4 m}\]             done clear
  B)
          \[\text{1}.\text{26 m}\]   done clear
  C)
  \[0.\text{7}0\text{ m}\]            done clear
  D)
          \[0.\text{63 m}\] done clear
  View Solution play_arrow

• question_answer236)
  It is desired to produce a real image on a screen using a convex lens of focal length 10 cm. The minimum distance between the object and the screen should be
  A)
   20cm done clear
  B)
   40cm   done clear
  C)
   100cm done clear
  D)
   the real image is obtained at all distances done clear
  View Solution play_arrow

• question_answer237)
  The refractive index of an equilateral prism is\[\sqrt{3}\] What is the angle of minimum deviation?
  A)
  \[45{}^\circ \] done clear
  B)
         \[60{}^\circ \]   done clear
  C)
  \[37{}^\circ \] done clear
  D)
         \[72{}^\circ \] done clear
  View Solution play_arrow

• question_answer238)
  A thin rod of length \[\frac{f}{3}\] is placed along the optic axis of a concave morror of focal length \[f\] such that its image which is real and elongated just thouches the rod. The magnification is
  A)
   \[\frac{3}{4}\]                   done clear
  B)
          \[\frac{1}{2}\] done clear
  C)
   \[\frac{3}{2}\]                     done clear
  D)
          none of the above done clear
  View Solution play_arrow

• question_answer239)
  Light passing from air to glass is refracted, as is light passing from glass to air. However when you look out of a window at the view outside, the light does not seem to have been distorted. This is because
  A)
   the angle of refraction is too small to observe done clear
  B)
   light incident upon the glass is partially reflected and this tends to mask the effect of refraction done clear
  C)
   the emergent ray is parallel to the incident ray and only displacement occurs   done clear
  D)
   the window pane is too thin for refraction to occur. done clear
  View Solution play_arrow

• question_answer240)
  Two plane mirrors \[{{M}_{1}}\] and \[{{M}_{2}}\] have a length of 2 m each and are 10 cm apart. A ray of light is incident on one end of mirror \[{{M}_{2}}\] at an angle of 30. The number of reflections light undergoes before reaching the other end is
  A)
   \[20\sqrt{3}\]     done clear
  B)
          \[100\] done clear
  C)
   150                        done clear
  D)
          200 done clear
  View Solution play_arrow

• question_answer241)
  In an achromatic combination of two prisms, the ratio of the deviations produced by the two prisms is 2 : 3, the ratio of their dispersive powers is
  A)
   2 : 3                       done clear
  B)
          3 : 2   done clear
  C)
   \[1:1\]                  done clear
  D)
          4 : 9 done clear
  View Solution play_arrow

• question_answer242)
  An object 10 cm from lens, has a virtual image at 10 cm from the object. The power of the lens is
  A)
   10 diopters       done clear
  B)
          \[-10\]diopters done clear
  C)
   5 diopters          done clear
  D)
          \[-\] diopters done clear
  View Solution play_arrow

• question_answer243)
  In a direct vision spectroscope, there are three identical crown glass prisms and two identical flints glass prism. If mean reflective indices of crown glass and flint glass be respectively 1.56 and 1.63 and angle of each crown glass prism be 6, then angle of each flint glass prism should be
  A)
  \[7{}^\circ \] done clear
  B)
         \[8{}^\circ \]   done clear
  C)
  \[9{}^\circ \] done clear
  D)
         \[10{}^\circ \] done clear
  View Solution play_arrow

• question_answer244)
  A person interested in deflecting a pencil of light through \[90{}^\circ \] prefers
  A)
   a plane glass plate silvered at the back done clear
  B)
   a right angled prism of refractive index \[>\sqrt{2}\]   done clear
  C)
   any ordinary prism done clear
  D)
   two plane mirrors done clear
  View Solution play_arrow

• question_answer245)
  When a wave is refracted
  A)
   its path must change done clear
  B)
   its amplitude should change done clear
  C)
   its velocity must change   done clear
  D)
   its frequency must change done clear
  View Solution play_arrow

• question_answer246)
  The minimum refracting angle of a prism of refractive index \[\mu \] for any ray of light incident not to emerge from the other face is
  A)
   \[{{\sin }^{-1}}\frac{1}{\mu }\] done clear
  B)
   \[2{{\sin }^{-1}}\frac{1}{\mu }\] done clear
  C)
   \[2{{\tan }^{-1}}\mu \] done clear
  D)
   twice the critical angle of prism   done clear
  View Solution play_arrow

• question_answer247)
  Light is incident from a medium into air at two possible angles of incidence \[\text{1}\text{.2}0\] and\[\text{2}\text{.4}0\]. In the medium, the light travels 3 cm in \[0.\text{2}\] ns, the ray will
  A)
   suffer total internal reflection in both cases done clear
  B)
   suffer total internal reflection in case 2 only done clear
  C)
   have 100% transmission in case 1 done clear
  D)
   have partial reflection and partial transmission in case 2   done clear
  View Solution play_arrow

• question_answer248)
   A substance is behaving as convex lens in air and concave in water, then its refractive index is
  A)
   smaller than air  done clear
  B)
                      greater than both air and water        done clear
  C)
   greater than air but less than water     done clear
  D)
   almost equal to water done clear
  View Solution play_arrow

• question_answer249)
  A ray of light undergoes deviation of \[30{}^\circ \] when incident on an equilateral prism of refractive index  \[\sqrt{2}\] . The angle made by the ray inside the prism with the base of the prism is
  A)
  \[30{}^\circ \] done clear
  B)
         \[45{}^\circ \] done clear
  C)
  \[60{}^\circ \] done clear
  D)
          zero   done clear
  View Solution play_arrow

• question_answer250)
  The phenomenon of dispersion arises because of
  A)
   the decomposition of a white light beam by a prism done clear
  B)
   the refraction of light done clear
  C)
   the refractive index of the prism material being different for different wave length   done clear
  D)
   the corpuscular nature of light done clear
  View Solution play_arrow

• question_answer251)
  Two prisms made of diamond \[\left( \mu =\text{ 2}\text{.4}0 \right)\] and glass \[\left( \mu \text{ }=\text{ 1}\text{.5}0 \right)\] have equal angle of prisms. The ratio deviations produced by them is
  A)
  \[\text{2}\text{.4 }:\text{ 1}\text{.5}\]           done clear
  B)
          1 : 1 done clear
  C)
  \[\text{2}\text{.8 }:\text{ 1}\]                      done clear
  D)
          none of these done clear
  View Solution play_arrow

• question_answer252)
  The sun subtends an angle of \[1/2{}^\circ \] at the surface of the earth. A converging lens of focal length 100 cm is used to obtain the image of the sun on to a screen. The diameter of the image formed is nearly
  A)
   1 mm                    done clear
  B)
          9 mm   done clear
  C)
   18mm                  done clear
  D)
          150cm done clear
  View Solution play_arrow

• question_answer253)
  A convex mirror has a focal length of 20 cm. A real object is placed at a distance of 20 cm from the pole of the mirror and in front of the mirror, The mirror produces an image at
  A)
   infinity                 done clear
  B)
          20 cm done clear
  C)
   40cm                    done clear
  D)
          10cm done clear
  E)
         None of these   done clear
  View Solution play_arrow

• question_answer254)
  In a concave mirror, an object is placed a distance \[{{d}_{1}}\]from the focus and the real image is formed at a distance dg from the focus. Then the focal length of the mirror is                      
  A)
   \[\sqrt{{{d}_{1}}{{d}_{2}}}\]         done clear
  B)
          \[{{d}_{1}}{{d}_{2}}\] done clear
  C)
   \[\frac{{{d}_{1}}{{d}_{2}}}{2}\]  done clear
  D)
          \[\sqrt{{{d}_{1}}/{{d}_{2}}}\] done clear
  View Solution play_arrow

• question_answer255)
  The focal length of a lens of refractive index 3/2 in air is 30 cm. What will be its focal length when is immersed in water of refractive index 4/3?
  A)
   60 cm                   done clear
  B)
          120 cm   done clear
  C)
   240 cm                 done clear
  D)
          None of these done clear
  View Solution play_arrow

• question_answer256)
  A rectangular slab of thickness 8 cm is placed on a figure. Eye is kept exactly above the slab. If the refractive index of glass is\[\text{1}\text{.6}\], then the figure will appear raised by
  A)
   \[\text{4}\text{.9}\]cm                 done clear
  B)
   5cm                    done clear
  C)
   3cm                         done clear
  D)
   4cm                        done clear
  View Solution play_arrow

• question_answer257)
  A ray of light is incident normally on one of the faces of a prism of apex angle \[30{}^\circ \] and refractive index \[\sqrt{2}\]. The angle of deviation of the ray is
  A)
   zero                      done clear
  B)
         \[90{}^\circ \] done clear
  C)
  \[15{}^\circ \]   done clear
  D)
         \[45{}^\circ \] done clear
  View Solution play_arrow

• question_answer258)
  All of the following statements are correct except
  A)
   The magnification produced by a convex mirror is always less then one done clear
  B)
   A virtual, erect, same sized image can be obtained by using a plane mirror done clear
  C)
   A virtual, erect, magnified image can be formed using a concave mirror done clear
  D)
   A real, inverted, same sized image can be formed using a convex mirror   done clear
  View Solution play_arrow

• question_answer259)
  A luminous object is placed at a distance of 30 cm from the convex lens of focal length 20 cm. On the other side of the lens, at what distance from the lens a convex mirror of radius of curvature 10 cm be placed in order to have an upright image of the object coincidental with it?
  A)
   12 cm                   done clear
  B)
          30 cm done clear
  C)
   50 cm                   done clear
  D)
          60 cm   done clear
  View Solution play_arrow

• question_answer260)
  A plane mirror which is at first 1 metre from an object, is then moved back 0-5 metre parallel to itself. The image will then move from its position
  A)
   1 metre back       done clear
  B)
          1 metre forward done clear
  C)
   \[0.\text{5}\]metre back   done clear
  D)
          \[0.\text{5}\]metre forward done clear
  View Solution play_arrow

• question_answer261)
  Two mirrors inclined to each other produces five images of an object placed between them. If the angle between them is reduced by \[30{}^\circ \], what will be the number of images seen in the two mirrors?
  A)
   15                          done clear
  B)
          12 done clear
  C)
   13                          done clear
  D)
          11   done clear
  View Solution play_arrow

• question_answer262)
  A ray of light making an angle \[10{}^\circ \] with the horizontal is incident on a plane mirror making angle\[\theta \]with the horizontal. What should be the value of \[\theta \] so that the reflected ray goes vertically upward?
  A)
  \[30{}^\circ \] done clear
  B)
         \[40{}^\circ \] done clear
  C)
  \[50{}^\circ \]   done clear
  D)
         \[60{}^\circ \] done clear
  View Solution play_arrow

• question_answer263)
  The angle between the incidental ray and the reflected ray from a plane mirror is \[60{}^\circ \]. Through what angle is the reflected ray deviate with respect to the incident ray?
  A)
   \[150{}^\circ \] done clear
  B)
          \[120{}^\circ \]   done clear
  C)
  \[90{}^\circ \] done clear
  D)
         \[60{}^\circ \] done clear
  View Solution play_arrow

• question_answer264)
  A concave mirror forms the real image of an object which is magnified 4 times. The object is moved 3 cm away, the magnification of the image is 3 times/What is the focal length of the mirror?
  A)
   3 cm                      done clear
  B)
          4 cm done clear
  C)
   12 cm                   done clear
  D)
          36 cm   done clear
  View Solution play_arrow

• question_answer265)
  The largest distance of the image from a convex mirror of focal length 10 cm can be
  A)
   30cm done clear
  B)
   infinite done clear
  C)
   10cm   done clear
  D)
   Dependes on the position of the object done clear
  View Solution play_arrow

• question_answer266)
  The diameter of the moon is about 3500 km. What will be the diameter of the image formed by a concave mirror of radius 3m? Assume that the distance of the moon is about \[\text{3}\text{.5 }\times \text{ 1}0\text{5}\]km.
  A)
   5 mm                    done clear
  B)
          10 mm done clear
  C)
   15 mm                   done clear
  D)
          20 mm done clear
  View Solution play_arrow

• question_answer267)
  A concave mirror of focal length fin air is used in a medium of refractive index 2. What will be the focal length of the mirror in the medium?
  A)
   \[4f\]                                    done clear
  B)
   \[2f\] done clear
  C)
   \[f\text{/}2\]                    done clear
  D)
          None of the above   done clear
  View Solution play_arrow

• question_answer268)
  A glass cube of edge 1 cm and \[=\text{ 1}.\text{5}\]has a small spot at the centre. What parts of the cube face must be covered to prevent the spot from being seen, no matter what the direction of viewing?
  A)
   With a circular path of radius 0.45 cm   done clear
  B)
   With a square of side 1 cm done clear
  C)
   It cannot be covered done clear
  D)
   None of the above done clear
  View Solution play_arrow

• question_answer269)
  Two lenses of power \[+\text{12 D}\]and \[-2D\] are put in contact. What is their equivalent focal length?
  A)
   10 cm                     done clear
  B)
          \[\text{12}\text{.5 cm}\] done clear
  C)
  \[\text{16}\text{.6 cm}\]              done clear
  D)
          \[\text{8}\text{.33 cm}\] done clear
  View Solution play_arrow