optical instruments questions with solutions

Showing 1–10 of 32 questions

• MCQmediumGeometrical opticsoptical instruments

  A normal eye is not able to see objects closer than 25 cm because

  Options

  • Option A

    the focal length of the eye is 25 cm

  • Option B

    the distance of the retina from the eye-lens is 25 cm

  • Option C

    the eye is not able to decrease the distance between the eye-lens and the retina beyond a limit

  • Option D

    the eye is not able to decrease the focal length beyond a limit.

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• MCQmediumGeometrical opticsoptical instruments

  The focal length of the objective of a compound microscope is fo and its distance from the eyepiece is L. The object is placed at a distance u from the objective. For proper working of the instrument,

  Options

  • Option A

    L < u

  • Option B

    L > u

  • Option C

    fo < L < 2fo

  • Option D

    L > 2fo

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• NumericeasyGeometrical opticsoptical instruments

  In a microscope the objective is having focal length f₀ = 2 cm and eye-piece is having focal length fₑ = 4 cm. The tube length is 32 cm. The magnification produced by this microscope for normal adjustment is ___________.

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  JEE Mains 202621 January Morning Shift

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• MCQmediumGeometrical opticsoptical instruments

  An astronomical telescope has an eyepiece of focal length 5 cm. If the angular magnification in normal adjustment is 10, the distance between the objective and the eye piece is

  Options

  • Option A

    45 cm

  • Option B

    50 cm

  • Option C

    55 cm

  • Option D

    110 cm

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• MCQmediumGeometrical opticsoptical instruments

  In a compound microscope, the magnified virtual image is formed at a distance of 25 cm from the eye-piece. The focal length of its objective lens is 1 cm. If the magnification is 100 and the tube length of the microscope is 20 cm, then the focal length of the eye-piece lens (in cm) is __________.

  Options

  • Option A

    4.48

  • Option B

    2.24

  • Option C

    8.96

  • Option D

    5.48

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• MCQmediumGeometrical opticsoptical instruments

  In the case of hypermetropia

  Options

  • Option A

    the image of a near object is formed behind the retina

  • Option B

    the image of a distant object is formed on front of the retina

  • Option C

    a concave lens should be used for correction

  • Option D

    a convex lens should not be used for correction

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• MCQmediumGeometrical opticsoptical instruments

  A person has been using spectacles of power -1.0 diopter for distant vision and a separate reading glass of power 2.0 diopters. What is the least distance of distinct vision for this person?

  Options

  • Option A

    10 cm

  • Option B

    40 cm

  • Option C

    30 cm

  • Option D

    50 cm

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  JEE Mains30 January 2023Shift 1Morning Shift

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• MCQeasyGeometrical opticsoptical instruments

  A scientist is observing a bacteria through a compound microscope. For better analysis and to improve its resolving power he should: (Select the best option)

  Options

  • Option A

    Increase the wavelength of the light

  • Option B

    Increase the refractive index of the medium between the object and objective lens

  • Option C

    Decrease the focal length of the eye piece

  • Option D

    Decrease the diameter of the objective lens

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  JEE Mains29 January 2023Shift 2Evening Shift

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• MCQmediumGeometrical opticsoptical instruments

  An object viewed from a near point distance of 25 cm, using a microscopic lens with magnification '6', gives an unresolved image. A resolved image is observed at infinite distance with a total magnification double the earlier using an eyepiece along with the given lens and a tube of length 0.6 m. The focal length of the eyepiece is equal to_______cm.

  Options

  • Option A

    12.5

  • Option B

    50

  • Option C

    26

  • Option D

    25

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• MCQmediumGeometrical opticsoptical instruments

  If we need a magnification of 375 from a compound microscope of tube length 150 mm and an objective of focal length 5 mm, the focal length of the eye-piece, should be close to:

  Options

  • Option A

    22 mm

  • Option B

    12 mm

  • Option C

    33 mm

  • Option D

    2 mm

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