入にゅう射しゃ光こう線せん

noun

incident ray; incident light ray

Technical term in physics for a ray of light that strikes a surface or interface.

• 入にゅう射しゃ光こう線せんの角かく度どを変かえると、反はん射しゃ光こう線せんの方ほう向こうも変かわる。

  If you change the angle of the incident ray, the direction of the reflected ray also changes.