Question

The reflection of how many rays will give you a clear image?

Answer 1

Only one ray from a point is actually required to form an image. But the image so formed will be very dark like in pinhole cameras. To get a luminous and bright image, we have to admit multiple rays emerging from a single point. Every ray forms a dark image at different places. Lens/curved mirrors manipulate the rays so as to make them meet at a point. Many dark images overlapping at the same point gives a bright and sharp image.