(a) A student suffering from myopia is not able to see distinctly the objects placed beyond 5m

CBSE Class 10 CBSE Class 10 Science
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(a) A student suffering from myopia is not able to see distinctly the objects placed beyond 5m. List two possible reasons due to which this defect of vision may have arisen.

  1. why the student is unable to see distinctly the objects placed beyond 5m from his eyes.
  2. the type of the corrective lens used to restore proper vision and how this defect is corrected by the use of this lens.

(b) If, in this case, the numerical value of the focal length of the corrective lens is 5m, find the power of the lens as per the new Cartesian sign convention.

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(a) Two possible reasons :

  • The eye ball size might have got elongated.
  • The eye lens is more thick than its normal its normal thickness during its power of accomodation.

(b) f = - 5 m (since, lens is concave) ; P = ?

image

Power of correcting lens is - 0.2 D and this correcting lens is concave lens.