Question

1) A lens forms virtual and magnified image of an object placed near to it.

a) Identify the nature of the lens.

b) Where you will place the object to get such image.

2) Use appropriate terms for following:

a) Point on retina which is insensitive to light.

b) Ability to adjust the focal length of eye lens to see near and far objects.​

Answer 1

Answer:

Explanation:

1) A lens forms virtual and magnified image of an object placed near to it.

Question a) Identify the nature of the lens.

Answer :- The lens is convex lens.

Question b) Where you will place the object to get such image.

Answer :- The object must be placed between F1 and Optical centre(O) of the lens.

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2) Use appropriate terms for following:

a) Point on retina which is insensitive to light.

Answer :- Blind spot is the point on retina which is insensitive to light.

Blind Spot

It is the spot at which the the optic nerve and blood vessels leave the eyeball , so no image can be detected by this region.

Question b) Ability to adjust the focal length of eye lens to see near and far objects.

Answer :- Power of Accommodation is the ability the cilliary muscles adjust the focal length of the eye lens  to see near and far objects.

Loss of power of accommodation

When we get aged the cilliary muscles will lose their ability to adjust the focal length of the eye lens  to see near and far objects.This condition is known as Presbyopia.

Answer 2

Answer:

1)For getting an erect, magnified and virtual image of an object, we have to keep the object between F1 and the optical centre of a convex lens. The image is formed in the same

side of the lens.

a)concave lens is the nature of the lens.

b)The object must be placed between F1 and optical centre(O) of the lens..

HOPE IT WILL HELP YOU....