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sp asked in Science & MathematicsPhysics · 8 years ago

Physics Help: It's nighttime, and you've dropped your goggles into a swimming pool?

It's nighttime, and you've dropped your goggles into a swimming pool that is 3.2 m deep. If you hold a laser pointer 1.0 m above the edge of the pool, you can illuminate the goggles if the laser beam enters the water 2.2 m from the edge. How far are the goggles from the edge of the pool?

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  • Vince 505
    Lv 6
    8 years ago
    Favorite Answer

    Laser angle with water surface is given by: Tan α = 1/2.2 = 0.4545/

    α = 24.44°.

    Laser angle with Normal = 90 - 24.44 = 65.56 °

    Assuming a red laser, refractive index in water is 1.331.

    Angle of refraction in water is given by:

    Ref Ind = Sin i / Sin r

    1.331 = Sin 65.56 / Sin r

    Sin r = 0.9104 / 1.331 = 0.684

    Angle r = 43.16°

    For the path in water:

    Tan 43.16 = x / 3.2

    x = 3 m where x is the lateral displacement of the laser ince it hits the water

    So the goggles are 2.2 + 3.0 = 5.2 m from edge of pool

  • ?
    Lv 4
    4 years ago

    Nighttime Goggles

    Source(s): https://shrinkurl.im/a8zvZ
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