By analyzing objects in front of a spherical mirror, perpendicular to the mirror's main axis, we can reach some important conclusions.
An object can be real or virtual. In the case of mirrors, we say that the object is virtual if it is "behind" the mirror. In the case of spherical mirrors the image of an object can be bigger, smaller or equal the size of the object. Image may still appear inverted in relation to the object. If there is no inversion we say that it is right.
Fundamental equation of spherical mirrors
Given the focal length and position of the object, it is possible to analytically determine the position of the image through the Gauss equation, which is expressed by: