Question

a person uses a lens of power plus 3D to normalise Vision near point of hypermetropic eye is

Answer 1

Answer:

Explanation:

1m

1.66m

2m

0.66m

Answer :

A

Solution :

Focal length of the lens f= 1003 cm

By lens formula 1f = 1v−1u

⇒1+100/3=1v−1−25

⇒v=−100cm=−1m

Answer 2

Hypermetropia is an eye condition in which, when closer to the face, the person is unable to see things clearly. The normal near point of an eye is 25 cm.

• The target must be at a distance of atleast 25 cm for normal people to see clearly. The virtual image must be for med at 100 cm for a hypermetropic eye with a near point of 1 m (100 cm) to see an object placed at 25 cm.
• According to the formula - 1/focal length (f)= 1/ object distance (u) + 1/ image distance (v)  or  1/f = 1/u -1/v.

• Focal length of the lens f =100/3 cm

        By lens formula = 1f = 1v − 1u

        = 1 + 100/3 = 1v − 1/−25

        = v = − 100cm =

        = − 1m

• Therefore, the vision near point of hypermetropic eye is 1m.