Let us begin this lecture which has roughly two parts;

1. the history of light and its understanding through the centuries

and

2. the electromagnetic nature of light

A brief history of light

Various optical devices and optical phenomena have been known since close to 4000 years. The optical devices of ancient time includes mirrors, burning glasses, lenses and other magnifying devices.

Accordingly various properties and laws of light were understood and developed since these times. E.g.

a. light was understood to propagate rectilinearly and 

b. light was understood to reflect and refract.