危き険けん角かく度ど

noun

critical angle

Technical term used in physics, optics, and engineering for the angle of incidence beyond which total internal reflection occurs, or more generally the angle at which a system becomes unstable.

• 光ひかりが水みずから空くう気きへ進すすむとき、危き険けん角かく度どを超こえると全ぜん反はん射しゃが起おこる。

  When light travels from water to air, total reflection occurs if it exceeds the critical angle.

• この斜しゃ面めんの危き険けん角かく度どは約やく30度どで、それ以い上じょうだと土ど砂しゃ崩くずれの危き険けんがある。

  The critical angle of this slope is about 30 degrees; beyond that, there is a risk of landslide.