# Chapter 15

## 14 terms · Refraction terms

### Angle of Incidence

the angle that a line makes with a line perpendicular to the surface at the point of incidence

### Index of Refraction

the ratio of the velocity of light in a vacuum to that in a medium

### Concave Lens

a lens such that a parallel beam of light passing through it is caused to diverge or spread out

nearsightedness

### Critical Angle

the smallest angle of incidence for which light is totally reflected

### Chromatic Aberrations

dif. colors that blend at dif. angles in the lents and focus at dif. places.... achromatic lens to fix this

### Angle of Refraction

the angle between a refracted ray and a line perpendicular to the surface between the two media at the point of refraction

### Snell's Law

Equation describing the angle of refraction for a light ray passing from one medium to another, given by n₁sinθ₁ = n₂sinθ₂, where n is the index of refraction

### Focal Point

a point of convergence of light (or other radiation) or a point from which it diverges

farsightedness

### Atmospheric Refraction

a mirage, which is a false appearance due to difference in light and speed

### Refraction

the amount by which a propagating wave is bent

### Convex Lens

lens such that a beam of light passing through it is brought to a focal point

### Total Internal Reflection

the complete reflection that takes place within a substance when the angle of incidence of light striking the surface boundary is less than the critical angle