JEE Main & Advanced Physics Ray Optics Question Bank

done Microscope and Telescope Total Questions - 120

• question_answer1)
  The focal lengths of the objective and eye-lens of a microscope are 1 cm and 5 cm respectively. If the magnifying power for the relaxed eye is 45, then the length of the tube is                                        [CPMT 1979]
  A)
             30 cm                                       done clear
  B)
                                 25 cm done clear
  C)
             15 cm                                       done clear
  D)
             12 cm done clear
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• question_answer2)
  In a compound microscope magnification will be large, if the focal length of the eye piece is [CPMT 1984]
  A)
             Large                                        done clear
  B)
             Smaller  done clear
  C)
             Equal to that of objective        done clear
  D)
             Less than that of objective done clear
  View Solution play_arrow

• question_answer3)
  The focal length of the objective lens of a compound microscope is         [CPMT 1985; MNR 1986; MP PET 1997]
  A)
             Equal to the focal length of its eye piece  done clear
  B)
             Less than the focal length of eye piece  done clear
  C)
             Greater than the focal length of eye piece  done clear
  D)
             Any of the above three  done clear
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• question_answer4)
  Microscope is an optical instrument which 
  A)
             Enlarges the object  done clear
  B)
             Increases the visual angle formed by the object at the eye               done clear
  C)
             Decreases the visual angle formed by the object at the eye done clear
  D)
             Brings the object nearer  done clear
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• question_answer5)
  Magnifying power of a simple microscope is (when final image is formed at D = 25 cm from eye) [MP PET 1996; BVP 2003]
  A)
             \[\frac{D}{f}\]                       done clear
  B)
             \[1+\frac{D}{f}\]  done clear
  C)
             \[1+\frac{f}{D}\]                  done clear
  D)
             \[1-\frac{D}{f}\]  done clear
  View Solution play_arrow

• question_answer6)
  If in compound microscope m1 and m2 be the linear magnification of the objective lens and eye lens respectively, then magnifying power of the compound microscope will be  [CPMT 1985; KCET 1994]
  A)
             \[{{m}_{1}}-{{m}_{2}}\]      done clear
  B)
    \[\sqrt{{{m}_{1}}+{{m}_{2}}}\]  done clear
  C)
             \[({{m}_{1}}+{{m}_{2}})/2\]   done clear
  D)
             \[{{m}_{1}}\times {{m}_{2}}\]  done clear
  View Solution play_arrow

• question_answer7)
  For which of the following colour, the magnifying power of a microscope will be maximum 
  A)
             White colour                         done clear
  B)
             Red colour  done clear
  C)
             Violet colour                         done clear
  D)
             Yellow colour  done clear
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• question_answer8)
  The length of the compound microscope is 14 cm. The magnifying power for relaxed eye is 25. If the focal length of eye lens is 5 cm, then the object distance for objective lens will be                                                   [Pb. PMT 2002]
  A)
             1.8 cm                                      done clear
  B)
             1.5 cm  done clear
  C)
             2.1 cm                                      done clear
  D)
             2.4 cm  done clear
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• question_answer9)
  If the focal length of objective and eye lens are 1.2 cm and 3 cm respectively and the object is put 1.25 cm away from the objective lens and the final image is formed at infinity. The magnifying power of the microscope is 
  A)
             150                                            done clear
  B)
             200  done clear
  C)
             250                                            done clear
  D)
             400  done clear
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• question_answer10)
  The focal length of objective and eye lens of a microscope are 4 cm and 8 cm respectively. If the least distance of distinct vision is 24 cm and object distance is 4.5 cm from the objective lens, then the magnifying power of the microscope will be
  A)
             18   done clear
  B)
             32  done clear
  C)
             64  done clear
  D)
             20   done clear
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• question_answer11)
  When the length of a microscope tube increases, its magnifying power                                                 [MNR 1986]
  A)
             Decreases                              done clear
  B)
             Increases   done clear
  C)
             Does not change                 done clear
  D)
             May decrease or increase  done clear
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• question_answer12)
  In a compound microscope, if the objective produces an image Io  and the eye piece produces an image Ie, then [MP PET 1990]
  A)
             Io is virtual but Ie is real   done clear
  B)
             Io is real but Ie is virtual  done clear
  C)
             Io and Ie are both real   done clear
  D)
             Io and Ie are both virtual  done clear
  View Solution play_arrow

• question_answer13)
  The magnifying power of a simple microscope can be increased, if we use eye-piece of                 [MP PMT 1986]
  A)
             Higher focal length             done clear
  B)
             Smaller focal length done clear
  C)
             Higher diameter                  done clear
  D)
             Smaller diameter   done clear
  View Solution play_arrow

• question_answer14)
  An electron microscope is superior to an optical microscope in                                                   [CPMT 1984]
  A)
             Having better resolving power   done clear
  B)
             Being easy to handle   done clear
  C)
             Low cost   done clear
  D)
             Quickness of observation  done clear
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• question_answer15)
  The magnifying power of a microscope with an objective of 5 mm focal length is 400. The length of its tube is 20 cm. Then the focal length of the eye-piece is                   [MP PMT 1991]
  A)
             200 cm                                     done clear
  B)
             160 cm   done clear
  C)
             2.5 cm                                      done clear
  D)
              0.1 cm   done clear
  View Solution play_arrow

• question_answer16)
  The maximum magnification that can be obtained with a convex lens of focal length 2.5 cm is (the least distance of distinct vision is 25 cm)                                                             [MP PET 2003]
  A)
             10   done clear
  B)
             0.1 done clear
  C)
             62.5                                           done clear
  D)
             11 done clear
  View Solution play_arrow

• question_answer17)
  When the object is self-luminous, the resolving power of a microscope is given by the expression
  A)
             \[\frac{2\mu \sin \theta }{1.22\,\lambda }\]               done clear
  B)
             \[\frac{\mu \sin \theta }{\lambda }\] done clear
  C)
             \[\frac{2\mu \cos \theta }{1.22\ \lambda }\]              done clear
  D)
             \[\frac{2\mu }{\lambda }\] done clear
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• question_answer18)
  The power of two convex lenses A and B are 8 diopters and 4 diopters respectively. If they are to be used as a simple microscope, the magnification of   
  A)
             B will be greater than A   done clear
  B)
             A will be greater than B  done clear
  C)
             The information is incomplete  done clear
  D)
             None of the above  done clear
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• question_answer19)
  Finger prints are observed by the use of  
  A)
             Telescope                              done clear
  B)
             Microscope  done clear
  C)
             Gallilean telescope             done clear
  D)
             Concave lens  done clear
  View Solution play_arrow

• question_answer20)
  To produce magnified erect image of a far object, we will be required along with a convex lens, is            [MNR 1983]
  A)
             Another convex lens         done clear
  B)
             Concave lens   done clear
  C)
             A plane mirror                      done clear
  D)
             A concave mirror  done clear
  View Solution play_arrow

• question_answer21)
  In order to increase the magnifying power of a compound microscope   [JIPMER 1986; MP PMT 1997]
  A)
             The focal lengths of the objective and the eye piece should be small done clear
  B)
             Objective should have small focal length and the eye piece large done clear
  C)
             Both should have large focal lengths done clear
  D)
             The objective should have large focal length and eye piece should have small done clear
  View Solution play_arrow

• question_answer22)
  If the focal length of the objective lens is increased then  [MP PMT 1994]
  A)
             Magnifying power of microscope will increase but that of telescope will decrease done clear
  B)
             Magnifying power of microscope and telescope both will increase done clear
  C)
             Magnifying power of microscope and telescope both will decrease done clear
  D)
             Magnifying power of microscope will decrease but that of telescope will increase done clear
  View Solution play_arrow

• question_answer23)
  The magnification produced by the objective lens and the eye lens of a compound microscope are 25 and 6 respectively. The magnifying power of this microscope is  [Manipal MEE 1995; DPMT 2002]
  A)
             19   done clear
  B)
             31 done clear
  C)
             150 done clear
  D)
             \[\sqrt{150}\] done clear
  View Solution play_arrow

• question_answer24)
  The focal lengths of the objective and the eye-piece of a compound microscope are 2.0 cm and 3.0 cm respectively. The distance between the objective and the eye-piece is 15.0 cm. The final image formed by the eye-piece is at infinity. The two lenses are thin. The distances in cm of the object and the image produced by the objective measured from the objective lens are respectively [IIT 1995]
  A)
             2.4 and 12.0                           done clear
  B)
             2.4 and 15.0 done clear
  C)
             2.3 and 12.0                           done clear
  D)
             2.3 and 3.0 done clear
  View Solution play_arrow

• question_answer25)
  Resolving power of a microscope depends upon  [MP PET 1995]
  A)
             The focal length and aperture of the eye lens done clear
  B)
             The focal lengths of the objective and the eye lens done clear
  C)
             The apertures of the objective and the eye lens done clear
  D)
             The wavelength of light illuminating the object done clear
  View Solution play_arrow

• question_answer26)
  The objective lens of a compound microscope produces magnification of 10. In order to get an overall magnification of 100 when image is formed at 25 cm from the eye, the focal length of the eye lens should be
  A)
             4 cm                                          done clear
  B)
             10 cm done clear
  C)
             \[\frac{25}{9}\]cm              done clear
  D)
             9 cm done clear
  View Solution play_arrow

• question_answer27)
  A person using a lens as a simple microscope sees an                                      [AIIMS 1998]
  A)
             Inverted virtual image done clear
  B)
             Inverted real magnified image done clear
  C)
             Upright virtual image done clear
  D)
             Upright real magnified image done clear
  View Solution play_arrow

• question_answer28)
  Least distance of distinct vision is 25 cm. Magnifying power of simple microscope of focal length 5 cm is [EAMCET (Engg.) 1995; Pb. PMT 1999]
  A)
             1 / 5                                          done clear
  B)
             5 done clear
  C)
             1 / 6                                          done clear
  D)
             6 done clear
  View Solution play_arrow

• question_answer29)
  The objective of a compound microscope is essentially [SCRA 1998]
  A)
             A concave lens of small focal length and small aperture done clear
  B)
             Convex lens of small focal length and large aperture done clear
  C)
             Convex lens of large focal length and large aperture done clear
  D)
             Convex lens of small focal length and small aperture done clear
  View Solution play_arrow

• question_answer30)
  Resolving power of a microscope depends upon [DCE 1999]
  A)
             Wavelength of light used, directly done clear
  B)
             Wavelength of light used, inversely done clear
  C)
             Frequency of light used done clear
  D)
             Focal length of objective done clear
  View Solution play_arrow

• question_answer31)
  In a compound microscope cross-wires are fixed at the point [EAMCET (Engg.) 2000]
  A)
             Where the image is formed by the objective done clear
  B)
             Where the image is formed by the eye-piece done clear
  C)
             Where the focal point of the objective lies done clear
  D)
             Where the focal point of the eye-piece lies done clear
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• question_answer32)
  In a compound microscope, the focal lengths of two lenses are 1.5 cm and 6.25 cm an object is placed at 2 cm form objective and the final image is formed at 25 cm from eye lens. The distance between the two lenses is [EAMCET (Med.) 2000]
  A)
             6.00 cm                                    done clear
  B)
             7.75 cm done clear
  C)
             9.25 cm                                    done clear
  D)
             11.00 cm done clear
  View Solution play_arrow

• question_answer33)
  The length of the tube of a microscope is 10 cm. The focal lengths of the objective and eye lenses are 0.5 cm and 1.0 cm. The magnifying power of the microscope is about   [MP PMT 2000]
  A)
             5     done clear
  B)
             23 done clear
  C)
             166 done clear
  D)
             500 done clear
  View Solution play_arrow

• question_answer34)
  In a compound microscope, the intermediate image is  [IIT-JEE (Screening) 2000; MP PET 2005]
  A)
             Virtual, erect and magnified done clear
  B)
             Real, erect and magnified done clear
  C)
             Real, inverted and magnified done clear
  D)
             Virtual, erect and reduced done clear
  View Solution play_arrow

• question_answer35)
  The magnifying power of a compound microscope increases when                                          [MP PET 2000]
  A)
             The focal length of objective lens is increased and that of eye lens is decreased done clear
  B)
             The focal length of eye lens is increased and that of objective lens is decreased done clear
  C)
             Focal lengths of both objective and eye-piece are increased            done clear
  D)
             Focal lengths of both objective and eye-piece are decreased done clear
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• question_answer36)
  If the red light is replaced by blue light illuminating the object in a microscope the resolving power of the microscope                                                                   [DCE 2001]
  A)
             Decreases                              done clear
  B)
             Increases done clear
  C)
             Gets halved                           done clear
  D)
             Remains unchanged done clear
  View Solution play_arrow

• question_answer37)
  The magnifying power of a simple microscope is 6. The focal length of its lens in metres will be, if least distance of distinct vision is 25\[cm\]                                                      [MP PMT 2001]
  A)
             0.05                                           done clear
  B)
             0.06 done clear
  C)
             0.25                                           done clear
  D)
             0.12 done clear
  View Solution play_arrow

• question_answer38)
  Two points separated by a distance of 0.1 mm can just be resolved in a microscope when a light of wavelength 6000 Å is used. If the light of wavelength 4800Å is used  this limit of resolution becomes                                   [UPSEAT 2002]
  A)
             0.08 mm                                  done clear
  B)
             0.10 mm done clear
  C)
             0.12 mm                                  done clear
  D)
             0.06 mm done clear
  View Solution play_arrow

• question_answer39)
  A compound microscope has two lenses. The magnifying power of one is 5 and the combined magnifying power is 100. The magnifying power of the other lens is         [Kerala PMT 2002]
  A)
             10   done clear
  B)
             20 done clear
  C)
             50   done clear
  D)
             25 done clear
  View Solution play_arrow

• question_answer40)
  The angular magnification of a simple microscope can be increased by increasing                                              [Orissa JEE 2002]
  A)
             Focal length of lens            done clear
  B)
             Size of object done clear
  C)
             Aperture of lens                  done clear
  D)
             Power of lens done clear
  View Solution play_arrow

• question_answer41)
  Wavelength of light used in an optical instrument are \[{{\lambda }_{1}}=4000\]Å and \[{{\lambda }_{2}}=5000\]Å, then ratio of their respective resolving power (corresponding to \[{{\lambda }_{1}}\]and \[{{\lambda }_{2}})\]is  [AIEEE 2002]
  A)
             16 : 25                                      done clear
  B)
             9 : 1 done clear
  C)
             4 : 5                                           done clear
  D)
             5 : 4 done clear
  View Solution play_arrow

• question_answer42)
  The separation between two microscopic particles is measured \[{{P}_{A}}\] and \[{{P}_{B}}\] by two different lights of wavelength 2000 Å and 3000 Å respectively, then [AIEEE 2002]
  A)
             \[{{P}_{A}}>{{P}_{B}}\]     done clear
  B)
             \[{{P}_{A}}<{{P}_{B}}\] done clear
  C)
             \[{{P}_{A}}<3/2{{P}_{B}}\]      done clear
  D)
             \[{{P}_{A}}={{P}_{B}}\] done clear
  View Solution play_arrow

• question_answer43)
  The image formed by an objective of a compound microscope is                                               [AIEEE 2003]
  A)
             Virtual and enlarged          done clear
  B)
             Virtual and diminished done clear
  C)
             Real and diminished          done clear
  D)
             Real and enlarged done clear
  View Solution play_arrow

• question_answer44)
  An achromatic telescope objective is to be made by combining the lenses of flint and crown glasses. This proper choice is [CPMT 1977]
  A)
             Convergent of crown and divergent of flint  done clear
  B)
             Divergent of crown and convergent of flint  done clear
  C)
             Both divergent  done clear
  D)
             Both convergent   done clear
  View Solution play_arrow

• question_answer45)
  If Fo and Fe are the focal length of the objective and eye-piece respectively of a telescope, then its magnifying power will be CPMT 1977, 82, 97, 99, 2003;  SCRA 1994; KCET 1999; Pb. PMT 2000; BHU 2001;  DCE 2002; RPMT 2003; BCECE 2003, 04]
  A)
             \[{{F}_{o}}+{{F}_{e}}\]      done clear
  B)
             \[{{F}_{o}}\times {{F}_{e}}\]  done clear
  C)
             \[{{F}_{o}}/{{F}_{e}}\]      done clear
  D)
             \[\frac{1}{2}({{F}_{o}}+{{F}_{e}})\]  done clear
  View Solution play_arrow

• question_answer46)
  The magnifying power of a telescope can be increased by    [CPMT 1979]
  A)
             Increasing focal length of the system  done clear
  B)
             Fitting eye piece of high power  done clear
  C)
             Fitting eye piece of low power  done clear
  D)
             Increasing the distance of objects  done clear
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• question_answer47)
  A simple telescope, consisting of an objective of focal length 60 cm and a single eye lens of focal length 5 cm is focussed on a distant object is such a way that parallel rays comes out from the eye lens. If the object subtends an angle 2o at the objective, the angular width of the image  [CPMT 1979; NCERT 1980;  MP PET 1992; JIPMER 1997; UPSEAT 2001]
  A)
             10o  done clear
  B)
             24o done clear
  C)
             50o  done clear
  D)
             1/6o  done clear
  View Solution play_arrow

• question_answer48)
  The diameter of the objective of the telescope is 0.1 metre and wavelength of light is 6000 Å. Its resolving power would be approximately                                                             [MP PET 1997]
  A)
             \[7.32\times {{10}^{-6}}rad\]                                             done clear
  B)
             \[1.36\times {{10}^{6}}rad\]  done clear
  C)
             \[7.32\times {{10}^{-5}}rad\]                                             done clear
  D)
             \[1.36\times {{10}^{5}}rad\]  done clear
  View Solution play_arrow

• question_answer49)
  A photograph of the moon was taken with telescope. Later on, it was found that a housefly was sitting on the objective lens of the telescope. In photograph    [NCERT 1970; MP PET 1999]
  A)
             The image of housefly will be reduced  done clear
  B)
             There is a reduction in the intensity of the image  done clear
  C)
             There is an increase in the intensity of the image done clear
  D)
             The image of the housefly will be enlarged  done clear
  View Solution play_arrow

• question_answer50)
  For a telescope to have large resolving power the [CPMT 1980, 81, 85; MP PET 1994;  DCE 2001; AFMC 2005]
  A)
             Focal length of its objective should be large  done clear
  B)
             Focal length of its eye piece should be large done clear
  C)
             Focal length of its eye piece should be small done clear
  D)
             Aperture of its objective should be large  done clear
  View Solution play_arrow

• question_answer51)
  An observer looks at a tree of height 15 m with a telescope of magnifying power 10. To him, the tree appears [CPMT 1975]
  A)
             10 times taller                       done clear
  B)
             15 times taller  done clear
  C)
             10 times nearer                   done clear
  D)
             15 times nearer  done clear
  View Solution play_arrow

• question_answer52)
  The focal length of objective and eye lens of a astronomical telescope are respectively 2 m and 5 cm. Final image is formed at (i) least distance of distinct vision (ii) infinity. The magnifying power in both cases will be [MP PMT/PET 1988]
  A)
             ? 48, ? 40                                  done clear
  B)
    ? 40, ? 48 done clear
  C)
             ? 40, 48                                    done clear
  D)
             ? 48, 40  done clear
  View Solution play_arrow

• question_answer53)
  For observing a cricket match, a binocular is preferred to a terrestrial telescope because  
  A)
             The binocular gives the proper three dimensional view  done clear
  B)
             The binocular has shorter length  done clear
  C)
             The telescope does not give erect image  done clear
  D)
             Telescope have chromatic aberrations  done clear
  View Solution play_arrow

• question_answer54)
  To increase the magnifying power of telescope  (fo = focal length of the objective and fe = focal length of the eye lens) [MP PET/PMT 1988; MP PMT 1992, 94]
  A)
             fo should be large and fe should be small   done clear
  B)
             fo should be small and fe should be large   done clear
  C)
             fo and fe both should be large   done clear
  D)
             fo and fe both should be small done clear
  View Solution play_arrow

• question_answer55)
  Relative difference of focal lengths of objective and eye lens in the microscope and telescope is given as     [MH CET 2001]
  A)
             It is equal in both                done clear
  B)
             It is more in telescope   done clear
  C)
             It is more in microscope   done clear
  D)
             It may be more in any one done clear
  View Solution play_arrow

• question_answer56)
  If the telescope is reversed i.e. seen from the objective side 
  A)
             Object will appear very small   done clear
  B)
             Object will appear very large   done clear
  C)
             There will be no effect on the image formed by the telescope   done clear
  D)
             Image will be slightly greater than the earlier one done clear
  View Solution play_arrow

• question_answer57)
  The focal length of the objective of a terrestrial telescope is 80 cm and it is adjusted for parallel rays, then its magnifying power is 20. If the focal length of erecting lens is 20 cm, then full length of telescope will be  
  A)
             84 cm                                       done clear
  B)
     100 cm   done clear
  C)
             124 cm                                     done clear
  D)
     164 cm   done clear
  View Solution play_arrow

• question_answer58)
  An astronomical telescope has an angular magnification of magnitude 5 for distant objects. The separation between the objective and the eye piece is 36 cm and the final image is formed at infinity. The focal length fo of the objective and the focal length fe of the eye piece are [IIT 1989; MP PET 1995; JIPMER 2000]
  A)
             fo = 45 cm and fe = ? 9 cm   done clear
  B)
             fo = 7.2 cm and fe = 5 cm   done clear
  C)
             fo = 50 cm and fe = 10 cm   done clear
  D)
             fo = 30 cm and fe = 6 cm  done clear
  View Solution play_arrow

• question_answer59)
  In an astronomical telescope, the focal lengths of two lenses are 180 cm and 6 cm respectively. In normal adjustment, the magnifying power will be                   [MP PET 1990]
  A)
             1080                                          done clear
  B)
     200   done clear
  C)
             30                                              done clear
  D)
     186  done clear
  View Solution play_arrow

• question_answer60)
  The magnifying power of an astronomical telescope for relaxed vision is 16. On adjusting, the distance between the objective and eye lens is 34 cm. Then the focal length of objective and eye lens will be respectively         [MP PMT 1989]
  A)
             17 cm, 17 cm                         done clear
  B)
             20 cm, 14 cm   done clear
  C)
             32 cm, 2 cm                            done clear
  D)
             30 cm, 4 cm   done clear
  View Solution play_arrow

• question_answer61)
  In Gallilean telescope, if the powers of an objective and eye lens are respectively +1.25 D and ? 20 D, then for relaxed vision, the length and magnification will be 
  A)
             21.25 cm and 16                   done clear
  B)
             75 cm and 20   done clear
  C)
             75 cm and 16                         done clear
  D)
             8.5 cm and 21.25   done clear
  View Solution play_arrow

• question_answer62)
  The aperture of a telescope is made large, because [DPMT 1999]
  A)
             To increase the intensity of image   done clear
  B)
             To decrease the intensity of image   done clear
  C)
             To have greater magnification   done clear
  D)
             To have lesser resolution   done clear
  View Solution play_arrow

• question_answer63)
  In Gallilean telescope, the final image formed is
  A)
             Real, erect and enlarged   done clear
  B)
             Virtual, erect and enlarged   done clear
  C)
             Real, inverted and enlarged   done clear
  D)
             Virtual, inverted and enlarged   done clear
  View Solution play_arrow

• question_answer64)
  The magnifying power of a telescope is 9. When it is adjusted for parallel rays, the distance between the objective and the eye-piece is found to be 20 cm. The focal length of the two lenses are                                   [MP PMT 1986]
  A)
             18 cm, 2 cm                            done clear
  B)
             11 cm, 9 cm done clear
  C)
             10 cm, 10 cm                         done clear
  D)
             15 cm, 5 cm done clear
  View Solution play_arrow

• question_answer65)
  The focal length of the objective and eye piece of a telescope are respectively 60 cm and 10 cm. The magnitude of the magnifying power when the image is formed at infinity is                                            [MP PET 1991]
  A)
             50  done clear
  B)
             6   done clear
  C)
             70   done clear
  D)
             5  done clear
  View Solution play_arrow

• question_answer66)
  The magnifying power of an astronomical telescope is 8 and the distance between the two lenses is 54 cm. The focal length of eye lens and objective lens will be respectively [MP PMT 1991; CPMT 1991; Pb. PMT 2001]
  A)
             6 cm and 48 cm                    done clear
  B)
             48 cm and 6 cm   done clear
  C)
             8 cm and 64 cm                    done clear
  D)
             64 cm and 8 cm   done clear
  View Solution play_arrow

• question_answer67)
  An opera glass (Gallilean telescope) measures 9 cm from the objective to the eyepiece. The focal length of the objective is 15 cm. Its magnifying power is         [DPMT 1988]
  A)
             2.5 done clear
  B)
             2/5  done clear
  C)
             5/3                                            done clear
  D)
             0.4  done clear
  View Solution play_arrow

• question_answer68)
  When a telescope is adjusted for parallel light, the distance of the objective from the eye piece is found to be 80 cm. The magnifying power of the telescope is 19. The focal lengths of the lenses are [MP PMT 1992; Very similar to DPMT 2004]
  A)
             61 cm, 19 cm                         done clear
  B)
             40 cm, 40 cm done clear
  C)
             76 cm,  4 cm                           done clear
  D)
             50 cm, 30 cm done clear
  View Solution play_arrow

• question_answer69)
  A reflecting telescope utilizes                                  [CPMT 1983]
  A)
             A concave mirror                 done clear
  B)
             A convex mirror   done clear
  C)
             A prism                                    done clear
  D)
             A plano-convex lens done clear
  View Solution play_arrow

• question_answer70)
  The aperture of the objective lens of a telescope is made large so as to                 [AIEEE 2003; KCET 2003]
  A)
             Increase the magnifying power of the telescope done clear
  B)
             Increase the resolving power of the telescope done clear
  C)
             Make image aberration less done clear
  D)
             Focus on distant objects done clear
  View Solution play_arrow

• question_answer71)
  On which of the following does the magnifying power of a telescope depends                                   [MP PET 1992]
  A)
             The focal length of the objective only   done clear
  B)
             The diameter of aperture of the objective only done clear
  C)
             The focal length of the objective and that of the eye piece done clear
  D)
             The diameter of aperture of the objective and that of the eye piece  done clear
  View Solution play_arrow

• question_answer72)
  Large aperture of telescope are used for    [CPMT 1981; MP PMT 1995; AFMC 2000]
  A)
             Large image                           done clear
  B)
             Greater resolution   done clear
  C)
             Reducing lens aberration done clear
  D)
             Ease of manufacture done clear
  View Solution play_arrow

• question_answer73)
  Two convex lenses of focal lengths 0.3 m and 0.05 m are used to make a telescope. The distance kept between the two is                                                                      [MNR 1994]
  A)
             0.35 m                                      done clear
  B)
             0.25 m done clear
  C)
             0.175 m                                   done clear
  D)
             0.15 m done clear
  View Solution play_arrow

• question_answer74)
  The diameter of the objective lens of a telescope is 5.0 m and wavelength of light is 6000 Å. The limit of resolution of this telescope will be                                                       [MP PMT 1994]
  A)
             0.03 sec                                   done clear
  B)
             3.03 sec done clear
  C)
             0.06 sec                                   done clear
  D)
             0.15 sec done clear
  View Solution play_arrow

• question_answer75)
  All of the following statements are correct except [Manipal MEE 1995]
  A)
             The total length of an astronomical telescope is the sum of the focal lengths of its two lenses done clear
  B)
             The image formed by the astronomical telescope is always erect because the effect of the combination of the two lenses is divergent done clear
  C)
             The magnification of an astronomical telescope can be increased by decreasing the focal length of the eye-piece done clear
  D)
             The magnifying power of the refracting type of astronomical telescope is the ratio of the focal length of the objective to that of the eye-piece done clear
  View Solution play_arrow

• question_answer76)
  A terrestrial telescope is made by introducing an erecting lens of focal length f between the objective and eye piece lenses of an astronomical telescope. This causes the length of the telescope tube to increase by an amount equal to [KCEE 1996]
  A)
             f      done clear
  B)
             2f done clear
  C)
             3f    done clear
  D)
             4f done clear
  View Solution play_arrow

• question_answer77)
  The length of an astronomical telescope for normal vision (relaxed eye) (fo = focal length of objective lens and fe  = focal length of eye lens) is [EAMCET (Med.) 1995; CPMT 1999; BVP 2003]
  A)
             \[{{f}_{o}}\times {{f}_{e}}\]   done clear
  B)
             \[\frac{{{f}_{o}}}{{{f}_{e}}}\] done clear
  C)
             \[{{f}_{o}}+{{f}_{e}}\]       done clear
  D)
             \[{{f}_{o}}-{{f}_{e}}\] done clear
  View Solution play_arrow

• question_answer78)
  A Gallilean telescope has objective and eye-piece of focal lengths 200 cm and 2 cm respectively. The magnifying power of the telescope for normal vision is   [MP PMT 1996]
  A)
             90   done clear
  B)
             100 done clear
  C)
             108 done clear
  D)
             198 done clear
  View Solution play_arrow

• question_answer79)
  In an astronomical telescope, the focal length of the objective lens is 100 cm and of eye-piece is 2 cm. The magnifying power of the telescope for the normal eye is [MP PET 1997]
  A)
             50   done clear
  B)
             10 done clear
  C)
             100 done clear
  D)
             \[\frac{1}{50}\] done clear
  View Solution play_arrow

• question_answer80)
  When diameter of the aperture of the objective of an astronomical telescope is increased, its   [MP PMT 1997]
  A)
             Magnifying power is increased and resolving power is decreased done clear
  B)
             Magnifying power and resolving power both are increased done clear
  C)
             Magnifying power remains the same but resolving power is increased done clear
  D)
             Magnifying power and resolving power both are decreased done clear
  View Solution play_arrow

• question_answer81)
  The focal lengths of the objective and eye lenses of a telescope are respectively 200 cm and 5 cm. The maximum magnifying power of the telescope will be  [MP PMT/PET 1998; JIPMER 2001, 02]
  A)
             ? 40                                           done clear
  B)
             ? 48 done clear
  C)
             ? 60                                           done clear
  D)
             ? 100 done clear
  View Solution play_arrow

• question_answer82)
  The minimum magnifying power of a telescope is M, If the focal length of its eye lens is halved, the magnifying power will become                                                     [MP PMT/PET 1998]
  A)
             M / 2                                        done clear
  B)
             2 M done clear
  C)
             3 M                                           done clear
  D)
             4 M done clear
  View Solution play_arrow

• question_answer83)
  The astronomical telescope consists of objective and eye-piece. The focal length of the objective is [AIIMS 1998; BHU 2000]
  A)
             Equal to that of the eye-piece done clear
  B)
             Greater than that of the eye-piece done clear
  C)
             Shorter than that of the eye-piece done clear
  D)
             Five times shorter than that of the eye-piece done clear
  View Solution play_arrow

• question_answer84)
  Four convergent lenses have focal lengths 100 cm, 10 cm, 4 cm and 0.3 cm. For a telescope with maximum possible magnification, we choose the lenses of focal length [KCET 1994]
  A)
             100 cm, 0.3 cm                      done clear
  B)
             10 cm, 0.3 cm done clear
  C)
             10 cm, 4 cm                            done clear
  D)
             100 cm, 4 cm done clear
  View Solution play_arrow

• question_answer85)
  The focal length of objective and eye-piece of a telescope are 100 cm and 5 cm respectively. Final image is formed at least distance of distinct vision. The magnification of telescope is                                         [RPET 1997]
  A)
             20   done clear
  B)
             24 done clear
  C)
             30   done clear
  D)
             36 done clear
  View Solution play_arrow

• question_answer86)
  A planet is observed by an astronomical refracting telescope having an objective of focal length 16 m and an eye-piece of focal length 2 cm                                   [IIT-JEE 1992; Roorkee 2000]
  A)
             The distance between the objective and the eye-piece is 16.02 m done clear
  B)
             The angular magnification of the planet is 800 done clear
  C)
             The image of the planet is inverted done clear
  D)
             The objective is larger than the eye-piece done clear
  View Solution play_arrow

• question_answer87)
  If tube length of astronomical telescope is 105 cm and magnifying power is 20 for normal setting, calculate the focal length of objective                                                                     [AFMC 1994]
  A)
             100 cm                                     done clear
  B)
             10 cm done clear
  C)
             20 cm                                       done clear
  D)
             25 cm done clear
  View Solution play_arrow

• question_answer88)
  The length of a telescope is 36 cm. The focal lengths of its lenses can be                                                [Bihar MEE 1995]
  A)
             30 cm, 6 cm                            done clear
  B)
             ? 30 cm, ? 6 cm done clear
  C)
             30 cm, ? 6 cm                        done clear
  D)
             ? 30 cm, 6 cm done clear
  View Solution play_arrow

• question_answer89)
  An astronomical telescope of ten-fold angular magnification has a length of 44 cm. The focal length of the objective is [CBSE PMT 1997]
  A)
             4 cm                                          done clear
  B)
             40 cm done clear
  C)
             44 cm                                       done clear
  D)
             440 cm done clear
  View Solution play_arrow

• question_answer90)
  If both the object and image are at infinite distances form a refracting telescope its magnifying power will be equal to  [AMU (Engg.) 1999]
  A)
             The sum of the focal lengths of the objective and the eyepiece done clear
  B)
             The difference of the focal lengths of the two lenses done clear
  C)
             The ratio of the focal length of the objective and eyepiece done clear
  D)
             The ratio of the focal length of the eyepiece and objective done clear
  View Solution play_arrow

• question_answer91)
  The number of lenses in a terrestrial telescope is   [KCET 1999; MH CET 2003]
  A)
             Two                                          done clear
  B)
             Three done clear
  C)
             Four                                          done clear
  D)
             Six done clear
  View Solution play_arrow

• question_answer92)
  The focal lengths of the lenses of an astronomical telescope are 50 cm and 5 cm. The length of the telescope when the image is formed at the least distance of distinct vision is [EAMCET (Engg.) 2000]
  A)
             \[45\,cm\]                              done clear
  B)
             \[55\,cm\] done clear
  C)
             \[\frac{275}{6}\,cm\]         done clear
  D)
             \[\frac{325}{6}\,cm\] done clear
  View Solution play_arrow

• question_answer93)
  The focal lengths of the objective and eye-piece of a telescope are respectively 100 cm and 2 cm. The moon subtends an angle of \[{{0.5}^{o}}\,\]at the eye. If it is looked through the telescope, the angle subtended by the moon's image will be                                                                        [MP PMT 2000; DCE 2003]
  A)
             \[{{100}^{o}}\]                     done clear
  B)
             \[{{50}^{o}}\] done clear
  C)
             \[{{25}^{o}}\]                        done clear
  D)
             \[{{10}^{o}}\] done clear
  View Solution play_arrow

• question_answer94)
  The diameter of the objective of a telescope is a,  its magnifying power is m and wavelength of light is \[\lambda .\]The resolving power of the telescope is                                                         [MP PMT 2000]
  A)
             \[(1.22\,\lambda )/a\]      done clear
  B)
             \[(1.22\,a)/\lambda \] done clear
  C)
             \[\lambda m/(1.22a)\]      done clear
  D)
             \[a/(1.22\lambda \,)\] done clear
  View Solution play_arrow

• question_answer95)
  The sun's diameter is \[1.4\times {{10}^{9}}m\] and its distance from the earth is \[{{10}^{11}}m.\] The diameter of its image, formed by a convex lens of focal length \[2\,m\]will be   [MP PET 2000]
  A)
             0.7 cm                                      done clear
  B)
             1.4 cm done clear
  C)
             2.8 cm                                      done clear
  D)
             Zero (i.e. point image) done clear
  View Solution play_arrow

• question_answer96)
  In a terrestrial telescope, the focal length of objective is 90 cm, of inverting lens is \[5\,cm\]and of eye lens is \[6\,cm.\]If the final image is at 30 cm, then the magnification will be  [DPMT 2001]
  A)
             21   done clear
  B)
             12 done clear
  C)
             18   done clear
  D)
             15 done clear
  View Solution play_arrow

• question_answer97)
  The resolving power of a telescope depends on   [MP PET 2000, 01; DCE 2003]
  A)
             Focal length of eye lens done clear
  B)
             Focal length of objective lens done clear
  C)
             Length of the telescope done clear
  D)
             Diameter of the objective lens done clear
  View Solution play_arrow

• question_answer98)
  Four lenses of focal length + 15 cm, + 20cm,    + 150cm and + 250 cm are available for making an astronomical telescope. To produce the largest magnification, the focal length of the eye-piece should be  [CPMT 2001; AIIMS 2001]
  A)
             + 15 cm                                    done clear
  B)
             + 20 cm done clear
  C)
             +150 cm                                  done clear
  D)
             + 250 cm done clear
  View Solution play_arrow

• question_answer99)
  In an astronomical telescope, the focal length of objective lens and eye-piece are 150 cm and 6 cm respectively. In case when final image is formed at least distance of distinct vision. the magnifying power is   [KCET 2001]
  A)
             20   done clear
  B)
             30 done clear
  C)
             60   done clear
  D)
             15 done clear
  View Solution play_arrow

• question_answer100)
  In a laboratory four convex lenses \[{{L}_{1}},\,{{L}_{2}},\,{{L}_{3}}\] and \[{{L}_{4}}\] of focal lengths 2, 4, 6 and 8 cm respectively are available. Two of these lenses form a telescope of length 10 cm and magnifying power 4. The objective and eye lenses are [MP PMT 2001]
  A)
             \[{{L}_{2}},\,{{L}_{3}}\]     done clear
  B)
             \[{{L}_{1}},\,{{L}_{4}}\] done clear
  C)
             \[{{L}_{3}},\,{{L}_{2}}\]     done clear
  D)
             \[{{L}_{4}},\,{{L}_{1}}\] done clear
  View Solution play_arrow

• question_answer101)
  A telescope has an objective of focal length 50 cm and an eye piece of focal length 5 cm. The least distance of distinct vision is 25 cm. The telescope is focused for distinct vision on a scale 200 cm away. The separation between the objective and the eye-piece is                                              [Kerala PET 2002]
  A)
             75 \[cm\]                                done clear
  B)
             60 \[cm\] done clear
  C)
             71 \[cm\]                                done clear
  D)
             74 \[cm\] done clear
  View Solution play_arrow

• question_answer102)
  The resolving power of a telescope whose lens has a diameter of 1.22 m for a wavelength of 5000 Å is [Kerala PMT 2002]
  A)
             \[2\times {{10}^{5}}\]       done clear
  B)
             \[2\times {{10}^{6}}\] done clear
  C)
             \[2\times {{10}^{2}}\]       done clear
  D)
             \[2\times {{10}^{4}}\] done clear
  View Solution play_arrow

• question_answer103)
  To increase both the resolving power and magnifying power of a telescope         [Kerala PET 2002;  KCET  2002]
  A)
             Both the focal length and aperture of the objective has to be increased done clear
  B)
             The focal length of the objective has to be increased done clear
  C)
             The aperture of the objective has to be increased done clear
  D)
             The wavelength of light has to be decreased done clear
  View Solution play_arrow

• question_answer104)
  A Galileo telescope has an objective of focal length \[100cm\] and magnifying power 50. The distance between the two lenses in normal adjustment will be [BHU 2002; Pb. PET 2002]
  A)
             96 cm                                       done clear
  B)
             98 cm done clear
  C)
             102 cm                                     done clear
  D)
             104 cm done clear
  View Solution play_arrow

• question_answer105)
  An astronomical telescope has a magnifying power 10. The focal length of eyepiece is 20 cm. The focal length of objective is                    [MP PMT 2002, 03; Pb. PET 2004]
  A)
             2 cm                                          done clear
  B)
             200 cm done clear
  C)
             \[\frac{1}{2}cm\]                 done clear
  D)
             \[\frac{1}{200}cm\] done clear
  View Solution play_arrow

• question_answer106)
  A telescope of diameter 2m uses light of wavelength 5000 Å for viewing stars. The minimum angular separation between two stars whose image is just resolved by this telescope is  [MP PET 2003]
  A)
             \[4\times {{10}^{-4}}\]rad      done clear
  B)
             \[0.25\times {{10}^{-6}}\]rad done clear
  C)
             \[0.31\times {{10}^{-6}}\]rad                                            done clear
  D)
             \[5.0\times {{10}^{-3}}\]rad done clear
  View Solution play_arrow

• question_answer107)
  A simple magnifying lens is used in such a way that an image is formed at 25 cm away from the eye. In order to have 10 times magnification, the focal length of the lens should be                                           [MP PET 1990]
  A)
             5 cm                                          done clear
  B)
             2 cm done clear
  C)
             25 mm                                     done clear
  D)
             0.1 mm done clear
  View Solution play_arrow

• question_answer108)
  In a simple microscope, if the final image is located at infinity then its magnifying power is            [MP PMT 2004]      
  A)
             \[\frac{25}{f}\]                     done clear
  B)
             \[\frac{D}{26}\] done clear
  C)
             \[\frac{f}{25}\]                     done clear
  D)
             \[\frac{f}{D+1}\] done clear
  View Solution play_arrow

• question_answer109)
  In a compound microscope the objective of \[{{f}_{o}}\] and eyepiece of \[{{f}_{e}}\] are placed at distance L such that L equals [Kerala PMT 2004]
  A)
             \[{{f}_{o}}+{{f}_{e}}\] done clear
  B)
             \[{{f}_{o}}-{{f}_{e}}\] done clear
  C)
             Much greater than \[{{f}_{o}}\] or \[{{f}_{e}}\] done clear
  D)
             Much less than \[{{f}_{o}}\] or \[{{f}_{e}}\] (e)     Need not depend either value of focal lengths done clear
  View Solution play_arrow

• question_answer110)
  For a compound microscope, the focal lengths of object lens and eye lens are \[{{f}_{o}}\]and \[{{f}_{e}}\] respectively, then magnification will be done by microscope when                     [RPMT 2001]
  A)
             \[{{f}_{o}}={{f}_{e}}\]       done clear
  B)
             \[{{f}_{o}}>{{f}_{e}}\] done clear
  C)
             \[{{f}_{o}}<{{f}_{e}}\]       done clear
  D)
             None of these done clear
  View Solution play_arrow

• question_answer111)
  The angular resolution of a 10 cm diameter telescope at a wavelength of 5000 Å is of the order [CBSE PMT 2005]
  A)
             \[{{10}^{6}}rad\]                 done clear
  B)
             \[{{10}^{-2}}rad\] done clear
  C)
             \[{{10}^{-4}}rad\]                done clear
  D)
             \[{{10}^{-6}}rad\] done clear
  View Solution play_arrow

• question_answer112)
  The resolving power of an astronomical telescope is 0.2 seconds. If the central half portion of the objective lens is covered, the resolving power will be        [MP PMT 2004]
  A)
             0.1 sec                                      done clear
  B)
             0.2 sec done clear
  C)
             1.0 sec                                      done clear
  D)
             0.6 sec done clear
  View Solution play_arrow

• question_answer113)
  An astronomical telescope has objective and eye-piece lens of powers 0.5 D and 20 D respectively, its magnifying power will be                                                         [Pb. PET 2002]
  A)
             8     done clear
  B)
             20 done clear
  C)
             30   done clear
  D)
             40 done clear
  View Solution play_arrow

• question_answer114)
  Which of the following is not correct regarding the radio telescope                                          [BHU 2004]
  A)
             It cannot work at night done clear
  B)
             It can detect a very faint radio signal done clear
  C)
             It can be operated even in cloudy weather done clear
  D)
             It is much cheaper than optical telescope done clear
  View Solution play_arrow

• question_answer115)
  The diameter of objective of a telescope is 1m. Its resolving limit for the light of wave length 4538 Å, will be [Pb. PET 2003]
  A)
             \[5.54\times {{10}^{-7}}rad\] done clear
  B)
             \[2.54\times {{10}^{-4}}rad\] done clear
  C)
             \[6.54\times {{10}^{-7}}rad\] done clear
  D)
             None of these done clear
  View Solution play_arrow

• question_answer116)
  A telescope has an objective lens of focal length 200 cm and an eye piece with focal length 2 cm. If this telescope is used to see a 50 meter  tall building at a distance of 2 km, what is the height of the image of the building formed by the objective lens                                                              [AIIMS 2005]
  A)
             5 cm                                          done clear
  B)
             10 cm done clear
  C)
             1 cm                                          done clear
  D)
             2 cm done clear
  View Solution play_arrow

• question_answer117)
  Magnification of a compound microscope is 30. Focal length of eye-piece is 5 cm and the image is formed at a distance of distinct vision of 25 cm. The magnification of the objective lens is                                              [DPMT 2005]
  A)
             6     done clear
  B)
             5 done clear
  C)
             7.5  done clear
  D)
             10 done clear
  View Solution play_arrow

• question_answer118)
  At Kavalur in India, the astronomers using a telescope whose objective had a diameter of one meter started using a telescope of diameter 2.54 m. This resulted in   [KCET 2005]
  A)
             The increase in the resolving power by 2.54 times for the same l done clear
  B)
             The increase in the limiting angle by 2.54 times for the same l done clear
  C)
             Decrease in resolving power done clear
  D)
             No effect on the limiting angle done clear
  View Solution play_arrow

• question_answer119)
  A Galileo telescope has an objective of focal length 100 cm and magnifying power 50. The distance between the two lenses in normal adjustment will be     [BCECE 2005]
  A)
             98 cm                                       done clear
  B)
             100 cm done clear
  C)
             150 cm                                     done clear
  D)
             200 cm done clear
  View Solution play_arrow

• question_answer120)
  A compound microscope has an eye piece of focal length 10 cm and an objective of focal length 4 cm. Calculate the magnification, if an object is kept at a distance of 5 cm from the objective so that final image is formed at the least distance vision (20 cm)                                                              [UP SEAT 2005]
  A)
             12   done clear
  B)
             11   done clear
  C)
             10   done clear
  D)
             13 done clear
  View Solution play_arrow