JEE Main & Advanced Physics Ray Optics Question Bank

done Total Internal Reflection Total Questions - 46

• question_answer1)
  A  cut diamond sparkles because of its [NCERT 1974; RPET 1996; AFMC 2005]
  A)
             Hardness done clear
  B)
                                 High refractive index done clear
  C)
             Emission of light by the diamond done clear
  D)
             Absorption of light by the diamond done clear
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• question_answer2)
  A diver in a swimming pool wants to signal his distress to a person lying on the edge of the pool by flashing his water proof flash light                                                                         [NCERT 1972]
  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 the total internal reflection done clear
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• question_answer3)
  Finger prints on a piece of paper may be detected by sprinkling fluorescent powder on the paper and then looking it into                                                                      [MP PET/PMT 1988]
  A)
             Mercury light                        done clear
  B)
             Sunlight done clear
  C)
             Infrared light                         done clear
  D)
             Ultraviolet light done clear
  View Solution play_arrow

• question_answer4)
  Critical angle of light passing from glass to air is minimum for                       [NCERT 1975; RPMT 1999; MP PMT 2002]
  A)
             Red                                           done clear
  B)
             Green done clear
  C)
             Yellow                                      done clear
  D)
             Violet done clear
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• question_answer5)
  The wavelength  of light in two liquids 'x' and 'y' is \[3500\text{ }{AA}\text{ }and\text{ }7000\text{ }{AA}\] , then the critical angle of x  relative to y will be
  A)
  \[60{}^\circ \] done clear
  B)
  \[45{}^\circ \] done clear
  C)
  \[30{}^\circ \] done clear
  D)
  \[15{}^\circ \] done clear
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• question_answer6)
  A fish is a little away below the surface of a lake. If the critical angle is 49°, then the fish could see things above the water surface within an angular range of \[{{\theta }^{o}}\] where [MP PMT 1986]
  A)
             \[\theta ={{49}^{o}}\] done clear
  B)
             \[\theta ={{90}^{o}}\] done clear
  C)
             \[\theta ={{98}^{o}}\] done clear
  D)
             \[\theta =24\frac{{{1}^{o}}}{2}\] done clear
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• question_answer7)
  If the critical angle for total internal reflection from a medium to vacuum is \[30{}^\circ \], the velocity of light in the medium is                          [CPMT 1972; MH CET 2000;  KCET 2000; BCECE 2003; RPMT 2003]
  A)
  \[3\times {{10}^{8}}\] m/s      done clear
  B)
  \[1.5\times {{10}^{8}}\] m/s done clear
  C)
  \[6\times {{10}^{8}}\] m/s      done clear
  D)
  \[\sqrt{3}\times {{10}^{8}}\]m/s done clear
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• question_answer8)
  A ray of light is incident at an angle i from denser to rare medium. The reflected and the refracted rays are mutually perpendicular. The angle of reflection and the angle of refraction are respectively r and r' , then the critical angle will be                         [IIT-JEE 1983; MP PET 1995;  CBSE PMT 1996; MP PMT 1985, 99; Pb. PET 2002]
  A)
  \[{{\sin }^{-1}}(\sin \,r)\] done clear
  B)
  \[{{\sin }^{-1}}\,(\tan r')\] done clear
  C)
  \[{{\sin }^{-1}}\,(\tan i)\] done clear
  D)
  \[{{\tan }^{-1}}(\sin i)\] done clear
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• question_answer9)
  For total internal reflection to take place, the angle of incidence i and the refractive index \[\mu \] of the medium must satisfy the inequality                                                 [MP PET 1994]
  A)
             \[\frac{1}{\sin i}<\mu \]   done clear
  B)
             \[\frac{1}{\sin i}>\mu \] done clear
  C)
             \[\sin i<\mu \]                      done clear
  D)
             \[\sin i>\mu \] done clear
  View Solution play_arrow

• question_answer10)
  Total internal reflection of light is possible when light enters from                            [CPMT 1973; MP PMT 1994]
  A)
             Air to glass                             done clear
  B)
             Vacuum to air done clear
  C)
             Air to water                           done clear
  D)
             Water to air done clear
  View Solution play_arrow

• question_answer11)
  Total internal reflection of a ray of light is possible when the (\[{{i}_{c}}\]= critical angle, \[i=\]angle of incidence) [NCERT 1977; MP PMT 1994]
  A)
             Ray goes from denser medium to rarer medium and \[i<{{i}_{c}}\] done clear
  B)
             Ray goes from denser medium to rarer medium and \[i>{{i}_{c}}\] done clear
  C)
             Ray goes from rarer medium to denser medium and \[i>{{i}_{c}}\] done clear
  D)
             Ray goes from rarer medium to denser medium and \[i<{{i}_{c}}\] done clear
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• question_answer12)
  A diver at a depth of 12m in water (\[\mu =4/3)\]sees the sky in a cone of semi-vertical angle [KCET 1999; Pb. PMT 2002; MP PMT 1995, 2003]
  A)
             \[{{\sin }^{-1}}(4/3)\]        done clear
  B)
             \[{{\tan }^{-1}}(4/3)\] done clear
  C)
             \[{{\sin }^{-1}}(3/4)\]        done clear
  D)
             90° done clear
  View Solution play_arrow

• question_answer13)
  Critical angle is that angle of incidence in the denser medium for which the angle of refraction in rarer medium is [MP PMT 1996]
  A)
  \[0{}^\circ \] done clear
  B)
  \[57{}^\circ \] done clear
  C)
  \[90{}^\circ \] done clear
  D)
  \[180{}^\circ \] done clear
  View Solution play_arrow

• question_answer14)
  The critical angle for diamond (refractive index = 2) is [MP PET 2003]
  A)
  \[20{}^\circ \] done clear
  B)
  \[60{}^\circ \] done clear
  C)
  \[45{}^\circ \] done clear
  D)
  \[30{}^\circ \] done clear
  View Solution play_arrow

• question_answer15)
  The reason for shining of air bubble in water is [MP PET 1997; KCET 1999]
  A)
             Diffraction of light               done clear
  B)
             Dispersion of light done clear
  C)
             Scattering of light                done clear
  D)
             Total internal reflection of light done clear
  View Solution play_arrow

• question_answer16)
  With respect to air critical angle in a medium for light of red colour \[[{{\lambda }_{1}}]\] is q. Other facts remaining same, critical angle for light of yellow colour \[[{{\lambda }_{2}}\]]  will be          [MP PET 1999]
  A)
             \[\theta \]                              done clear
  B)
             More than \[\theta \] done clear
  C)
             Less than \[\theta \]          done clear
  D)
             \[\frac{\theta {{\lambda }_{1}}}{{{\lambda }_{2}}}\] done clear
  View Solution play_arrow

• question_answer17)
  'Mirage' is a phenomenon due to [AIIMS 1998; MP PET 2002; AFMC 2003]
  A)
             Reflection of light done clear
  B)
             Refraction of light done clear
  C)
             Total internal reflection of light done clear
  D)
             Diffraction of light done clear
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• question_answer18)
  A ray of light travelling in a transparent medium falls on a surface separating the medium from air at an angle of incidence of 45°. The ray undergoes total internal reflection. If n is the refractive index of the medium with respect to air, select the possible value (s) of n from the following [IIT-JEE 1998]
  A)
             1.3  done clear
  B)
             1.4 done clear
  C)
             1.5  done clear
  D)
             1.6 done clear
  View Solution play_arrow

• question_answer19)
  When a ray of light emerges from a block of glass, the critical angle is                                      [KCET 1994]
  A)
             Equal to the angle of reflection done clear
  B)
             The angle between the refracted ray and the normal done clear
  C)
             The angle of incidence for which the refracted ray travels along the glass-air boundary done clear
  D)
             The angle of incidence done clear
  View Solution play_arrow

• question_answer20)
  The phenomenon utilised in an optical fibre is [KCET 1994; AMU 1995; CBSE PMT 2001; DCE 1999, 2000, 01, 02; AIEEE 2002]
  A)
             Refraction                              done clear
  B)
             Interference done clear
  C)
             Polarization                           done clear
  D)
             Total internal reflection done clear
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• question_answer21)
  The refractive index of water is 4 / 3 and that of glass is 5/3.  What will be the critical angle for the ray of light entering water from the glass                                                                 [RPMT 1996]
  A)
             \[{{\sin }^{-1}}\frac{4}{5}\]     done clear
  B)
             \[{{\sin }^{-1}}\frac{5}{4}\] done clear
  C)
             \[{{\sin }^{-1}}\]\[\frac{1}{2}\]                                          done clear
  D)
             \[{{\sin }^{-1}}\frac{2}{1}\] done clear
  View Solution play_arrow

• question_answer22)
  Total internal reflection is possible when light rays travel [RPMT 1999]
  A)
             Air to water                           done clear
  B)
             Air to glass done clear
  C)
             Glass to water                      done clear
  D)
             Water to glass done clear
  View Solution play_arrow

• question_answer23)
  The velocity of light in a medium is half its velocity in air.  If ray of light emerges from such a medium into air, the angle of incidence, at which it will be totally internally reflected,   is [Roorkee 1999]
  A)
  \[{{15}^{o}}\] done clear
  B)
  \[{{30}^{o}}\] done clear
  C)
  \[{{45}^{o}}\] done clear
  D)
  \[{{60}^{o}}\] done clear
  View Solution play_arrow

• question_answer24)
  A ray of light propagates from glass (refractive index = 3/2) to water (refractive index = 4/3).  The value of the critical angle                                       [JIPMER 1999; UPSEAT 2001; MP PMT 2000, 03]
  A)
             sin?1(1/2)                                done clear
  B)
             \[{{\sin }^{-1}}\left( \frac{\sqrt{8}}{9} \right)\] done clear
  C)
             \[{{\sin }^{-1}}(8/9)\]        done clear
  D)
             \[{{\sin }^{-1}}(5/7)\] done clear
  View Solution play_arrow

• question_answer25)
  Relation between critical angles of water and glass is [CBSE PMT 2000; Pb. PET 2000; CPMT 2001]
  A)
             Cw > Cg                                     done clear
  B)
             Cw < Cg done clear
  C)
             Cw = Cg                                     done clear
  D)
             Cw = Cg = 0 done clear
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• question_answer26)
  If critical angle for a material to air is 30o, the refractive index of the material will be                         [MP PET 2001]
  A)
             1.0 done clear
  B)
             1.5 done clear
  C)
             2.0  done clear
  D)
             2.5 done clear
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• question_answer27)
  The refractive index of water is 1.33. The direction in which a man under water should look to see the setting sun is [MP PET 1991; Kerala PET 2002; Pb. PET 2003]
  A)
  \[{{49}^{o}}\] to the horizontal          done clear
  B)
  \[{{90}^{o}}\] with the vertical done clear
  C)
  \[{{49}^{o}}\] to the vertical                done clear
  D)
  Along the horizontal done clear
  View Solution play_arrow

• question_answer28)
  Optical fibres are related with                                 [AFMC 2002]
  A)
             Communication                   done clear
  B)
             Light done clear
  C)
             Computer                              done clear
  D)
             None of these done clear
  View Solution play_arrow

• question_answer29)
  Brilliance of diamond is due to  [AIIMS 2002; MP PMT 2003]
  A)
             Shape                                      done clear
  B)
             Cutting done clear
  C)
             Reflection                              done clear
  D)
             Total internal reflection done clear
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• question_answer30)
  A light ray from air is incident (as shown in figure) at one end of a glass fiber (refractive index m = 1.5) making an incidence angle of 60o on the lateral surface, so that it undergoes a total internal reflection.  How much time would it take to traverse the straight fiber of length 1 km   [Orissa JEE 2002]
  A)
             3.33 m sec done clear
  B)
             6.67 m sec done clear
  C)
             5.77 m sec done clear
  D)
             3.85 m sec done clear
  View Solution play_arrow

• question_answer31)
  Light wave enters from medium 1 to medium 2.  Its velocity in 2nd medium is double from 1st.  For total internal reflection the angle of incidence must be greater than     [CPMT 2002]
  A)
  \[{{30}^{o}}\] done clear
  B)
  \[{{60}^{o}}\] done clear
  C)
  \[{{45}^{o}}\] done clear
  D)
  \[{{90}^{o}}\] done clear
  View Solution play_arrow

• question_answer32)
  Consider telecommunication through optical fibres.  Which of the following statements is not true  [AIEEE 2003]
  A)
             Optical fibres may have homogeneous core with a suitable cladding done clear
  B)
             Optical fibres can be of graded refractive index done clear
  C)
             Optical fibres are subject to electromagnetic interference from outside     done clear
  D)
             Optical fibres have extremely low transmission loss done clear
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• question_answer33)
  The critical angle for a medium is \[{{60}^{o}}\]. The refractive index of the medium is                                    [MP PMT 2004]
  A)
             \[\frac{2}{\sqrt{3}}\]         done clear
  B)
             \[\frac{\sqrt{2}}{3}\] done clear
  C)
             \[\sqrt{3}\]                            done clear
  D)
             \[\frac{\sqrt{3}}{2}\] done clear
  View Solution play_arrow

• question_answer34)
  Glass has refractive index m with respect to air and the critical angle for a ray of light going from glass to air is q. If a ray of light is incident from air on the glass with angle of incidence q, the corresponding angle of refraction is [MP PMT 2004]
  A)
             \[{{\sin }^{-1}}\left( \frac{1}{\sqrt{\mu }} \right)\]   done clear
  B)
             \[{{90}^{o}}\] done clear
  C)
             \[{{\sin }^{-1}}\left( \frac{1}{{{\mu }^{2}}} \right)\] done clear
  D)
             \[{{\sin }^{-1}}\left( \frac{1}{\mu } \right)\] done clear
  View Solution play_arrow

• question_answer35)
  White light is incident on the interface of glass and air as shown in the figure. If green light is just totally internally reflected then the emerging ray in air contains  [IIT-JEE (Screening) 2004]
  A)
             Yellow, orange, red            done clear
  B)
             Violet, indigo, blue done clear
  C)
             All colours                              done clear
  D)
             All colours except green done clear
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• question_answer36)
  Material A has critical angle \[{{i}_{A}},\] and material B has critical angle \[{{i}_{B}}({{i}_{B}}>{{i}_{A}}).\] Then which of the following is true (i)       Light can be totally internally reflected when it passes from B to A (ii)      Light can be totally internally reflected when it passes from A to B (iii)     Critical angle for total internal reflection is \[{{i}_{B}}-{{i}_{A}}\] (iv)     Critical angle between A and B is \[{{\sin }^{-1}}\left( \frac{\sin {{i}_{A}}}{\sin {{i}_{B}}} \right)\] [UPSEAT 2004]
  A)
             (i) and (iii)                               done clear
  B)
             (i) and (iv) done clear
  C)
             (ii) and (iii)                              done clear
  D)
             (ii) and (iv) done clear
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• question_answer37)
  In the figure shown, for an angle of incidence \[{{45}^{o}},\] at the top surface, what is the minimum refractive index needed for total internal reflection at vertical face [DCE 2002]
  A)
             \[\frac{\sqrt{2}+1}{2}\] done clear
  B)
             \[\sqrt{\frac{3}{2}}\] done clear
  C)
             \[\sqrt{\frac{1}{2}}\] done clear
  D)
             \[\sqrt{2}+1\] done clear
  View Solution play_arrow

• question_answer38)
  Critical angle for light going from medium (i) to (ii) is q. The speed of light in medium (i) is v then speed in medium (ii) is  [DCE 2002]
  A)
             \[v(1-\cos \theta )\]          done clear
  B)
             \[v/\sin \theta \] done clear
  C)
             \[v/\cos \theta \]                done clear
  D)
             \[v(1-\sin \theta )\] done clear
  View Solution play_arrow

• question_answer39)
  If light travels a distance x in \[{{t}_{1}}\]sec in air and 10 x distance in \[{{t}_{2}}\]sec in a medium, the critical angle of the medium will be                                                                                                 [MH CET 2003]
  A)
             \[{{\tan }^{-1}}\left( \frac{{{t}_{1}}}{{{t}_{2}}} \right)\]        done clear
  B)
             \[{{\sin }^{-1}}\left( \frac{{{t}_{1}}}{{{t}_{2}}} \right)\] done clear
  C)
             \[{{\sin }^{-1}}\left( \frac{10{{t}_{1}}}{{{t}_{2}}} \right)\]    done clear
  D)
             \[{{\tan }^{-1}}\left( \frac{10{{t}_{1}}}{{{t}_{2}}} \right)\] done clear
  View Solution play_arrow

• question_answer40)
  The critical angle of a medium with respect to air is \[{{45}^{o}}\]. The refractive index of medium is                        [MH CET 2003]
  A)
             1.41                                           done clear
  B)
             1.2 done clear
  C)
             1.5  done clear
  D)
             2 done clear
  View Solution play_arrow

• question_answer41)
  An endoscope is employed by a physician to view the internal parts of a body organ. It is based on the principle of  [AIIMS 2004]
  A)
             Refraction                              done clear
  B)
             Reflection done clear
  C)
             Total internal reflection    done clear
  D)
             Dispersion done clear
  View Solution play_arrow

• question_answer42)
  A normally incident ray reflected at an angle of \[{{90}^{o}}\]. The value of critical angle is                                            [RPMT 1996]
  A)
             \[{{45}^{o}}\]                        done clear
  B)
             \[{{90}^{o}}\] done clear
  C)
             \[{{65}^{o}}\]                        done clear
  D)
             \[{{43.2}^{o}}\] done clear
  View Solution play_arrow

• question_answer43)
  The phenomena of total internal reflection is seen when angle of incidence is                                    [RPMT 2001]
  A)
             \[{{90}^{o}}\]                        done clear
  B)
             Greater than critical angle done clear
  C)
             Equal to critical angle         done clear
  D)
             \[{{0}^{o}}\] done clear
  View Solution play_arrow

• question_answer44)
  A fish looking up through the water sees the outside world contained in a circular horizon. If the refractive index of water is \[\frac{4}{3}\] and the fish is 12 cm below the surface, the radius of this circle in cm is [NCERT 1980; KCET 2002; AIEEE 2005; CPMT 2005]
  A)
             \[36\sqrt{5}\]                       done clear
  B)
             \[4\sqrt{5}\] done clear
  C)
             \[36\sqrt{7}\]                       done clear
  D)
             \[36/\sqrt{7}\] done clear
  View Solution play_arrow

• question_answer45)
  A point source of light is placed 4 m below the surface of water of refractive index 5 / 3. The minimum diameter of a disc which should be placed over the source on the surface of water to cut?off all light coming out of water is [CBSE PMT 1994; JIPMER 2001, 02]
  A)
             2 m                                            done clear
  B)
             6 m done clear
  C)
             4 m                                            done clear
  D)
             3 m done clear
  View Solution play_arrow

• question_answer46)
  A fist looking from within water sees the outside world through a circular horizon. If the fish \[\sqrt{7}\]cm below the surface of water, what will be the radius of the circular horizon                                          [Kerala PMT 2005]
  A)
             3.0 cm                                      done clear
  B)
             4.0 cm done clear
  C)
             4.5 cm                                      done clear
  D)
             5.0 cm done clear
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