1. For distant vision = −0.181 m, for near vision = 0.667 m The power P of a lens of focal length f is given by the relation P = 1/f(in metres) (i) Power of the lens used for correcting distant vision = −5.5 D Focal length of the required lens, f =1/P F = 1/-5.5 = -0.181ₘ The focal length of the lens fRead more

    For distant vision = −0.181 m, for near vision = 0.667 m
    The power P of a lens of focal length f is given by the relation
    P = 1/f(in metres)
    (i) Power of the lens used for correcting distant vision = −5.5 D
    Focal length of the required lens, f =1/P
    F = 1/-5.5 = -0.181ₘ
    The focal length of the lens for correcting distant vision is −0.181 m.
    (ii) Power of the lens used for correcting near vision = +1.5 D
    Focal length of the required lens, f =1/P
    F = 1/1.5 = +0.667ₘ

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  2. (c) The relaxation or contraction of ciliary muscles changes the curvature of the eye lens. The change in curvature of the eye lens changes the focal length of the eyes. Hence, the change in focal length of an eye lens is caused by the action of ciliary muscles. For more answers visit to website: htRead more

    (c) The relaxation or contraction of ciliary muscles changes the curvature of the eye lens. The change in curvature of the eye lens changes the focal length of the eyes. Hence, the change in focal length of an eye lens is caused by the action of ciliary muscles.

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  3. (c) The least distance of distinct vision is the minimum distance of an object to see clear and distinct image. It is 25 cm for a young adult with normal visions. For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-10/science/chapter-11/

    (c) The least distance of distinct vision is the minimum distance of an object to see clear and distinct image. It is 25 cm for a young adult with normal visions.

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  4. (d) The human eye forms the image of an object at its retina. For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-10/science/chapter-11/

    (d) The human eye forms the image of an object at its retina.

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  5. (b) Human eye can change the focal length of the eye lens to see the objects situated at various distances from the eye. This is possible due to the power of accommodation of the eye lens. For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-10/science/chapter-11/

    (b) Human eye can change the focal length of the eye lens to see the objects situated at various distances from the eye. This is possible due to the power of accommodation of the eye lens.

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