Question

If your eye glasses have focal length 60 cm ,what is your near point?

Answer 1

Answer:

between 25 cm and 60 cm

Step-by-step explanation:

This question shows that it is convex lens which is used by patients of hypermetrophic eye.The near point of normal eye is 25 cm.So he has no problem in seeing near objects but he has problem in seeing far objects.So, It is between 25 cm and 60 cm.

Answer 2

Answer:42.85 cm approximately

Step-by-step explanation:

Let us assume that the near point of a normal eye is 25 cm.

Now, any object placed in front of the lens will have its image formed at the near point of the eye.

Thus u = -25cm

v =?

f = 60cm

Now,

1/v -1/u = 1/f

=>1/v +1/25cm = 1/60cm

=>1/v = 1/60cm -1/25cm

=>1/v = -7/300cm

=>v = -300/7 cm ≈ -42.85cm

Thus, the near point of the eye is 42.85cm.