Distinguish between: Farsightedness and Nearsightedness. - Science and Technology 1

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Distinguish Between

Distinguish between:

Farsightedness and Nearsightedness.

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Solution

  Farsightedness Nearsightedness
1. This problem arises due to slight flattening of the eyeball. This problem arises due to slight elongation of the eyeball.
2. The curvature of the cornea and eye lens decreases so that the converging power becomes less. The curvature of the cornea and eye lens increases so that the converging power becomes more.
3. The distance between the eye lens and the retina decreases. The distance between the eye lens and the retina increases.
4. The near point of the eye shifts farther away from the eye. The far point of the eye shifts closer to eye.
5. A person suffering from this defect can see distant objects clearly but is unable to see nearby objects. A person suffering from this defect can see nearby objects clearly but is unable to see distant objects.
6. It can be corrected by using spectacles having convex lenses of suitable focal length. It can be corrected by using spectacles having concave lenses of suitable focal length.
Concept: Lens
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Chapter 7: Lenses - Distinguish between

RELATED QUESTIONS

The power of a lens is - 5D.

1) Find its focal length.

2) Name the type of lens.


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Concave lens and Convex lens.


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A concave lens is a converging lens.


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The point inside the lens on the principal axis through which light rays pass without changing their path is called _______.


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The image formed by _______ lens is always virtual and small.


Find the odd one out and give its explanation.


Find the odd one out and give its explanation.


Write the name.

The imaginary line passing through two optical centres of lens


Write an Explanation.

Centre of curvature of the lens


Write an Explanation.

Principal focus


Write scientific reason.

A convex lens is called a converging lens.


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An object at 2F1.


Explain with a ray diagram the position, size, and nature of the various images formed by a convex lens.

Object between F1 and O


The image formed by a lens is always virtual, erect and smaller in size than an object kept at different positions in front of it. Identify the nature of the lens.


State whether the following statement is True or False

A concave lens can be used to produce an enlarged and erect image.


State whether the following statement is True or False

A convex lens always produces a real image.


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The given figures show the path of light through lenses of two different types, represented by rectangular boxes A and B. What is the nature of lenses A and B?


Two different types of lenses are placed on a sheet of newspaper. How will you identify them without touching them?


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A point object is placed at a distance of 60 cm from a convex lens of a focal length of 30 cm. If a plane mirror were put perpendicular to the principal axis of the lens and at a distance of 40 cm from it, the final image would be formed at a distance of:


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The power of a convex lens of focal length 25 cm is ______.


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