Assertion: The focal length of objective lens in telescope i

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 Multiple Choice QuestionsMultiple Choice Questions

261.

Assertion:  A thick lens shows more chromatic aberration.

Reason:  Thick lens behave as many thin lenses.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


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262.

Assertion: The focal length of objective lens in telescope is much more than that of eye piece.

Reason: Telescope has high resolving power due to large focal length.

  • If both assertion and reason are true and reason is the correct explanation of assertion.

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


B.

If both assertion and reason are true but reason is not the correct explanation of assertion.

In telescope to have a large magnifying power, focal length of objective lens is kept large.To increase the magnifying power and resolving power, aperture of the objective lens is made large.


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263.

Two lens of focal lengths -20 cm and + 10 cm are put in combination, find the power of the combination

  • - 1 D

  • - 2 D

  • + 5 D

  • + 2 D


264.

A far sighted person has his near point 50 cm, find the power of lens he should use to see at 25 cm, clearly.

  • + 1 D

  • + 2 D

  • - 2 D

  • - 1 D


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265.

Assertion:  When a white light is passed through a lens, violet light is more refracted than red light. 

Reason:  Focal length for red light is greater than violet.

  • If both assertion and reason are true and reason is the correct expalnation of assertion.

  • If both assertion and reason are true but reason not the correct explanation of assertion.

  • If assertion is true but reason is false

  • If both assertion and reason are false.


266.

Assertion: Microscope magnifies the image. 

Reason: Angular magnification for image is more than object in microscope.

  • If both assertion and reason are true and reason is correct explanation of assertion.

  • If both assertion and reason are true but reason is not correct explanation of assertion.

  • If assertion is true but reason is false.

  • If both assertion and reason are false.


267.

Assertion: Magnification of a convex mirror is always positive, but that of a concave mirror may be both positive or negative. 

Reason:  It depends on the sign convention chosen.

  • If both assertion and reason are true but reason is the correct explanation of assertion.

  • If both assertion are reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is not true.

  • If both assertion and reason are false.


268.

For a person near point of vision is  100 cm. Then the power of lens he must wear so as to have normal vision, should be

  • + 1D

  • - 1D

  • + 3D

  • - 3D


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269.

A  convex  lens  of  refractive  index 32  has  a power of 2.5 D  in  a  liquid  of  refractive  index 2, then  the  new power  of  the  lens  is

  • - 1.25 D

  • - 1.5 D

  • 1.25 D

  • 1.5 D


270.

Which out of the following, cannot produce two coherent sources?

  • Lloyd's mirror

  • Fresnel biprism

  • Young's double slit

  • Prism


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