We learned at school that white object reflects all the light that falls on it. We also learned that a mirror reflects all light as well. However, we cannot see ourselves in a white object while we can see ourselves in a mirror.
What makes a mirror different from a white surface?
If both white surface and mirror reflect all the light that fall on them, then why don't they look the same?
The thing is that, A mirror is a surface from which light get totally reflected.
It have a polished surface. We generally see mirror effect from metal surface.
The light which come in strike at angle $\theta$ to the normal and reflect away at $\theta$ from the normal.
It is a surface which seems to be white but it reflect and disperse of all seven visible wavelength.
The surface is microscopically very rough. White surface are generally clothes, paints, non-metal, paper.
The light which come in strike at angle $\theta$ to the normal and reflect away at many various angle from the normal.
There is lot of distortion and dispersion of light.
That is why, a mirror $surface$ and white $surface$ are different.
A white object only appears white if white light is striking it. If only red light is striking it, it appears red. A mirror has less distortion than other surfaces so it reflects light in a straight line. You don't see the surface of the mirror but rather the objects from which the light originates.
NB, when I speak about white or red light, it's important to remember that light itself has no colour. Colours are merely how our brains interpret different wavelengths.
