Question

Give an example of the shadows converging at the point of contact.

Answer 1

If we are seeing a coloured poster, then we are seeing only the poster and not the coloured lights reflected fronts it. It is because light is invisible. The various colours reflected from the poster excite the retina of the eye, which in turn sends a message to the brain. It is the brain which finally makes out the colours of the poster. Thus, we can conclude that light is an invisible energy which causes in us sensation of vision.