spectral power density

例句：

1. 1.The spectrum of light from the sun is a fascinating study in physics.
   太阳光的光谱是物理学中一个引人入胜的研究课题。
2. 2. In this experiment, we are measuring the spectral power density of the light source.
   在这个实验中，我们正在测量光源的光谱功率密度。
3. 3. The spectral power density of the light reflected off the surface is used to determine its composition.
   表面反射的光的光谱功率密度被用来确定其组成。