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incidence

incidence

2 7.0
The angle at which a light beam hits a surface
  • noun
  • /ˈɪnsɪdəns/
  • Specialized
translation icon : incidencia
  • However, their bandwidth per angle of incidence is limited to a relatively narrow range.
  • incidence angle

This way, angle of incidence equals angle of reflection.

Examples

  • It's capable of angles of incidence that we couldn't otherwise see.

  • Imported malaria in Canada has not been examined recently in the context of increased international mobility, which may influence the incidence of imported and autochthonous cases.

    Academic text (2012)
  • The angle of incidence is equal to the speed...

  • This way, angle of incidence equals angle of reflection.

  • Even at grazing incidence, optical surfaces absorb rather than reflect high-energy photons.

    Academic text (2003)
  • In principle, if a particle in the circular billiard were launched with precisely the right angle of incidence to the boundary, it would execute a closed periodic orbit.

    Academic text (2005)
  • The irradiation technique (active or sham) had the laser probe positioned to promote a perpendicular incidence of LLLT.

    Academic text (2015)
  • The angle at which the ray hits the mirror is called the angle of incidence.

  • Because of the sun's low angle of incidence, very little direct sunlight hits the ground.

  • Even at grazing incidence, optical surfaces absorb rather than reflect high-energy photons.

Compounds

angle of incidence
  • Specialized
1 6.8

The angle between a light ray and a line at a right angle to the surface where they meet

incidence angle
  • Specialized
7.2

The angle between incoming light and a line at a right angle to the surface

relative incidence
  • Specialized
7.4

How often something happens compared with something else

Surface Forms

incidence singular
incidences plural

Morphology

incidence = incident (semi-transparent) = incident + ence

The optical meaning is closely connected to the learned base 'incident', but it is a specialized technical sense that many learners would not infer automatically.

Etymology

The word incidence comes from an old Latin word incidere, which meant 'to fall on' and is made of in- 'on' and cadere 'to fall'. In physics the idea is very literal: incidence is where a beam of light 'falls on' a surface and the angle it makes, which is why we talk about the 'angle of incidence'.