How do mirrors reflect light?
When light shines onto an object viewed in a mirror, the rays are reflected into the eye. The rays come from a position behind the mirror. The image is the sane size as the object and the same distance from the mirror. In the image, left is right and right becomes left. The angle that the light gets pointed on to the mirror is the same as the angle that gets reflected of the mirror!
Mirrors do not refract light. They reflect light. <><><><><> Well, not quite. Surface silvered mirrors truly only reflect light, but normal back silvered mirrors still have a transition boundary of glass at the front surface, so there will be some refraction, causing some distortion. This is why high performance mirrors, such as those in telescopes, are often front surface silvered.
As most paper's surface is rough at microscopic levels therefore they do reflect the light but the light reflected y them is scattered over a large surface due to its rough texture.......As they do not reflect light in a particular direction like mirrors therefore they seems not to reflect the light.....
In a PERFECT System with Perfect Mirrors reflecting 100% of the Energy that strikes it....two parallel mirrors will reflect light striking it at 90 degrees to their surfaces an INFINITE number of times. Of course that System does not exist. Mirrors are NOT 100% Reflective. It is impossible to make two flat objects Perfectly Parallel, and Introducing a Perfectly Perpendicular Light Beam into the System is NOT Possible either.
Concave mirrors are used because they will reflect a light source inside the curve in one general direction. To be more specific, the mirrors are close to parabolic. Parabolas have the property that light beams generated at the focal point of the parabola are all reflected parallel out of the mirror.