Looking at the myriad of stars in a dark night amazes a person. We suspect the prehistoric people were the first to ignite fire to cook their food and to warm their bodies in winter. There is clear evidence from the ruins of the ancient civilizations that, sun was considered god because of its tremendous light emitting power. The greatest light detector of all, is the human eye. Even today, the vision of eye is not fully understood.
Light is that entity which, permits vision with the help of eye.
Light is a form of energy. We do not see light, but perceive objects constructed by brain about their shape, color, texture and the state of motion. Sources of light are hot bodies, lightning, electric discharges, insects, and fire. Light stimulates vision. So much for the definition, frankly speaking nobody found the truth about light.