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影子为什么会变长变短

更新时间: 2020-07-05 00:00:00     

首先光是沿直线传播的,它遇到不透明物体时就会产生影子 当物体离光源,远时,所产生的影子长,当物体在光源正下方时,影子短,变长与变短的原因,是物体挡住了光束的直线传播,影子的长短与物体遮住光束数量有关。

关键词: 影子 为什么

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