Reflection of light from a mirror
When light rays traveling is a medium reaches the boundary of other medium,they return back to the first medium. This phenomenon of turning back oflight into the same medium after striking the boundary of other medium iscalled Reflection of Light.
We have learnt in the last chapter that Newton proposed the corpusculartheory that treats light as being composed of tiny particles. We use thistheory to describe reflection.
When light falls on the surface of an object, it may be absorbed, transmitted or reflected. If an object absorbs all the light which falls on it, it will appear black. For example, a black board appears black because it absorbs all the visible frequencies.
If an object transmits the light, that is, if the object allows the light to pass through itself, the object is said to be transparent. For example, an ordinary glass sheet transmits most of the light that falls on it and hence appears transparent. Most of the objects reflect some of the light which falls on their surface.
When a polished block of silver metal is illuminated with sunlight or any source of light, electrons in the atoms of the silver vibrate more energetically in response to the oscillating electric fields of the illuminating light. The energized electrons re-emit the light by which we see the dazzling. The process of sending back the light rays which fall on the surface of an object, is called reflection of light.