concave mirror

基本解释

The diameter of a sphere is four times the focal length of a concave mirror cut from it.
凹麪鏡如果是從圓球上切下來的，圓球的直逕會是凹麪鏡焦距的四倍。
Cool Earth’s insight was that if you coat only one half of a balloon, leaving the other transparent, the inner surface of the coated half will act as a concave mirror.
Cool Earth的想法是如果你衹鍍半個氣球，另一半是透明的，鍍層內表麪的那半起凹透鏡的作用。
Cool Earth's insight was that if you coat only one half of a balloon, leaving the other transparent, the inner surface of the coated half will act as a concave mirror.
酷地太陽能公司有個獨到的認識：如果衹給氣球的一半塗上金屬，讓另一半透光，那麽塗有金屬的那一半內表麪就會象一個凹麪鏡。

Cool Earth's insight was that if you coat only one half of a balloon, leaving the other transparent, the inner surface of the coated half will act as a concave mirror.
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