Property And Nature of Light


Refection is the process by which waves are 'bounced' away from a smooth or reflective surface.

Flat Mirror Reflection Diagram.  Flavio Spedalieri

Fig 1.0

Fig 1.0. This show the details involved with the reflection of a light wave, this also applies to other waves in the electromagnetic spectrum In this case, the reflective surface is a mirror, the incident ray (represented by the red line) is aimed at the mirror, a reflected ray (represented by the blue line) will then be bounced off the mirror. Depending on the quality of the reflective surface, and the material, you can reflect up to 99 % of the original energy (this is taking into account, the energy lost due to absorption)

The Law of Reflection:

    The angle of reflection is equal to the angle of incidence from the normal

Light is always reflected at an equal angle from the normal (represented by the green perforated line) as the angle from the normal and the incident ray in any given case.

Reflections In Mirrors:

Reflections In Mirror Diagram.  Flavio Spedalieri

Fig 1.1

Fig 1.1. This shows how a virtual Image (cannot be projected onto a screen) is produce by the reflection of the object. The reflected image appears 'behind' the mirror.

Convex Mirror Diagram.  Flavio Spedalieri

Fig 1.2

Fig 1.2. This shows the principle of reflection from a convex mirror, again the virtual image appears behind the mirror.

Concave Mirror Graphic

Fig 1.3

Fig 1.3. This shows how the use of a concave mirror is used to focus light to a point. One application of this type of device is in a solar furnace, the object to be heated is place at the focus point of the mirror. In this case, the law of reflection is maintained.