If the eye is kept very close to a coverging lens (focal length `= 10 cm`) and at the optical centre of the lens and an object is kept at distance 'd' of the object from the lebs so that its image can be seen clearly by the defect free eye is :
.

Options

A. 10 cm
B. 25 cm
C. `(50)/(3) cm`
D. `(50)/(7) cm`

Answer

A

Explanation

Similarly as in the previous problem
`(1)/(d)=(1)/(F)+(1)/(d')`
For maximum 'd',d' should be maximum i.e.
`d' = infty`
Substituting , `(1)/(d) =(1)/(F)+(1)/(infty) rArr d = f = 10 cm`.