principal angle of incidence

例句：

1. 1.The engineer calculated the principal angle of incidence for the project.
   工程师计算了该项目的主要入射角。
2. 2. The scientist measured the principal angle of incidence to determine the angle of refraction.
   科学家测量了入射角的主要角度以确定折射角。
3. 3. The physicist explained the concept of the principal angle of incidence in his lecture.
   物理学家在他的讲座中解释了入射角的主要概念。