Light essentially travels in a straight line. When it encounters a change in medium, that light will bend to travel in a new direction, but the outgoing path will still be straight.

The law of reflection states that the angle of incidence equals the angle of reflection. This is the angle as measured to the normal of the surface. Specular reflection occurs when light strikes a smooth and highly reflective surface. The light is reflected off in one direction and we get a very clear image. Diffuse reflection occurs when light strikes a rough surface. Light is scattered off the surface at various angles and we see an image that is fuzzy. For more on specular and diffuse reflection, try

A plane mirror is a mirror that is flat. When an object is placed in front of the mirror, the image appears to come from behind the mirror at the same distance as the object distance. The height of the object and the image will be
the same. The image, however, will be reversed left to right.
A real image is an image that can be projected on a screen. A real image will appear to form in front of a mirror. A virtual image cannot be projected. Virtual images
will appear to come from behind the mirror.

For Practice Problems, Try: Reflection Off A Plane Surface from DCPhysics