在物理学中,指能发出一定波长范围的电磁波(包括可见光与紫外线、红外线、X射线等不可见光)的物体。通常情况下指能发出可见光的发光体。凡物体本身能发光者,称做光源,又称发光体。如太阳、恒星、灯以及燃烧着的物质等都是光源。
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