finite beam source

例句：

1. 1. The finite beam source isused to generate a narrow beam of light.
   有限光束源用于产生一束窄光。
2. 2.In this experiment, the finite beam sourcewas used to measure the intensity of thelight.
   在这个实验中，有限光束源被用来测量光线的强度。
3. 3. The finitebeam source was placed at the focal pointof the lens to focus the light.
   有限光束源被放置在透镜的焦点处，以聚焦光线。