Basic Laws of Refraction

1. The incident ray, the reflected ray and the normal to the surface are in the same plane.
2. The path of a refracted ray at the interface of two media is exactly reversible.
Flat mirror: Reflective and polished flat surface.

Spherical mirror: Polished surface that can be considered as a portion of a reflective sphere. Spherical mirrors can be:
1. Concave or convergent (if the interior of the spherical surface is reflective).
2. Convex or divergent (if the outside of the surface is reflective).
Mirror equation: (Applicable to both concave and convex).
1 / p + 1 / q = 1 / f where f = R / 2
where: p = distance from the object
q = image distance
f = focal length
R = radius of curvature

Flat mirrors form upright images of the same size of the object and at the same distance behind the reflective surface than to which the object is placed in front of the surface.
The images are virtual (they cannot be captured on a screen). The images formed by spherical mirrors can be larger, smaller or of the same size as the objects.

Magnification / (side of mirror) = image size / object size = q / p
where: q = distance to the image
p = distance the object

p (+) if the object is in front of the mirror
q (+) if the image is real (it is in front of the mirror)
q (-) if the image is virtual (behind the mirror)

R and f are (+) for concave mirrors and (-) for convex ones.

Lens: Transparent object generally made of glass that alters the shape of a wave front that passes through it. Refracted light forms images analogous to mirrors. Lenses can be:
to) Convergent: Retracts and converges parallel light at a focal point beyond the lens. They are thicker in the middle than at the edges.
b) Divergent: Refracts and diverges parallel light from a point located in front of the lens. Its edges are thicker than its middle part.
The focal length f, of a lens is the distance from the optical center of the lens to one or other of its foci.
By the equation of the lenses (identical to the equation of the mirrors), the characteristics, size and location of the images are determined).
Dispersion: Separation of light in the wavelengths that compose it.
Right prisms make use of the principle of total internal reflection to deflect the path of light.
Polarization: Process by which the transverse oscillations of a wave motion are confined to a defined pattern. Polarization is a characteristic of shear waves. A longitudinal wave cannot be polarized.
Diffraction: Waves ability to deflect or change direction around obstacles in their path.
Duality of light: The contemporary point of view tells us that light in its propagation behaves like a wave, while it is corpuscular in nature when it interacts with matter. That is, a photon behaves like a wave when it propagates and like a particle when it interacts with matter.