Our topic for today is Introduction to Light. Light is a form of energy that enables us
to see all the things around us. The main source of light on the earth is the sun. Plants are able to prepare their own food
using sunlight. Some other objects also give out light. They are known as luminous objects. For example, bulbs, lamps, candles, etc. are luminous objects. While there are some objects that do not give out light. They are known as non luminous objects. For example table, cloth, bag, utensils, etc. are non luminous objects. Non luminous objects are generally of two types, transparent objects and opaque objects. Transparent objects are those that allow light to pass through them, like glass, water etc. While, opaque objects are those that do not allow light to pass through them, like wood, stone etc.