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. Power of lens is defined as the reciprocal of its focal length. If P is the power of a lens of focal length F in metres, then P= 1/f(in metres) The S.I. unit of power of a lens is Dioptre. It is denoted by D. 1 dioptre is defined as the power of a lens of focal length 1 metre. 1 D = 1 m−¹ For more aRead more

    Power of lens is defined as the reciprocal of its focal length. If P is the power of a lens of
    focal length F in metres, then
    P= 1/f(in metres)
    The S.I. unit of power of a lens is Dioptre. It is denoted by D.
    1 dioptre is defined as the power of a lens of focal length 1 metre.
    1 D = 1 m−¹

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  3. The light ray bends towards the normal. When a ray of light travels from an optically rarer medium to an optically denser medium, it gets bent towards the normal. Since water is optically denser than air, a ray of light travelling from air into the water will bend towards the normal. For more answerRead more

    The light ray bends towards the normal.
    When a ray of light travels from an optically rarer medium to an optically denser medium,
    it gets bent towards the normal. Since water is optically denser than air, a ray of light
    travelling from air into the water will bend towards the normal.

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  4. Power of a lens, P = 1/f (in meters) Power, P = 1.5d F = 1/1.5 = 10/15 = 0.66m A convex lens has a positive focal length. Hence, it is a convex lens or a converging lens. For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-10/science/chapter-10/

    Power of a lens, P = 1/f (in meters)
    Power, P = 1.5d
    F = 1/1.5 = 10/15 = 0.66m
    A convex lens has a positive focal length. Hence, it is a convex lens or a converging lens.

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  5. Power of a lens, P = 1/f (in meters) P = -2 D f = -1/2 = -0.5m A concave lens has a negative focal length. Hence, it is a concave lens. For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-10/science/chapter-10/

    Power of a lens, P = 1/f (in meters)
    P = -2 D
    f = -1/2 = -0.5m
    A concave lens has a negative focal length. Hence, it is a concave lens.

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