问题
名词解释
荧光现象
答案
参考答案：
叶绿素溶液在透射光下呈绿色，在反射光下呈红色，这种现象称为叶绿素的荧光现象。激发态的叶绿素分子回到基态时，可以以发光的形式释放能量。处在第一单线态的叶绿素分子回至基态时所发出的光称为荧光。由于能量的损耗，辐射出的光能必定低于吸收的光能，因此叶绿素荧光的波长要比吸收的波长长些。故为暗红色。
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荧光现象
参考答案：
叶绿素溶液在透射光下呈绿色，在反射光下呈红色，这种现象称为叶绿素的荧光现象。激发态的叶绿素分子回到基态时，可以以发光的形式释放能量。处在第一单线态的叶绿素分子回至基态时所发出的光称为荧光。由于能量的损耗，辐射出的光能必定低于吸收的光能，因此叶绿素荧光的波长要比吸收的波长长些。故为暗红色。
| 完形填空。 Everyone needs friends. We all like to 1 close to someone. 2 is nice to have a friend to talk, laugh, and do things with. 3 , sometimes we need to be alone. We don't always want people 4 . But we would feel lonely if we never have a friend. No two people are 5 . Friends sometimes don't get on well. That doesn't mean they no longer like each other. Most of the time they will make up and become 6 again. Sometimes friends move away. Then we feel very _ 7 . We miss them very much, and we can call them and write to them. It could be that we could even see them again. And we can 8 new friends. It is surprising to find out how much we like new people when we get to know them. There's more good news for people who have friends. They live longer than people who don't. Why? It could be that they are 9 . Being happy helps you stay well. Or it could be just knowing that someone cares. If someone cares about you, you take 10 care of yourself. | |||
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