The Nature of Light
The nature of light has two pivotal concepts; reflection and refraction. All objects must reflect light in order to be seen.
The basic law of reflection requires two rays of equal force; an incoming (incident) ray and an outgoing (reflected ray). Most objects display diffuse reflection, with light being reflected in all directions. All objects obey the law of reflection on a microscopic level, but if the irregularities on the surface of an object are larger than the wavelength
of light, which is usually the case, the light reflects off in all directions. The diagram demonstrates that for reflection to work, the angle of reflection must equal the angle of incidence.
of light, which is usually the case, the light reflects off in all directions. The diagram demonstrates that for reflection to work, the angle of reflection must equal the angle of incidence.
The diagram shows the refraction of light as it passes from a fast medium
to a slow medium or vise-versa. The red line is the normal, which is perpendicular to the surface of the medium. As the light passes through the second medium, the light bends towards the normal due to the greater density of the second medium than the first. The angle between the incoming ray and the normal is the angle of
incidence. The angle between the refracted ray and the normal is the angle of
refraction.
to a slow medium or vise-versa. The red line is the normal, which is perpendicular to the surface of the medium. As the light passes through the second medium, the light bends towards the normal due to the greater density of the second medium than the first. The angle between the incoming ray and the normal is the angle of
incidence. The angle between the refracted ray and the normal is the angle of
refraction.