Final answer:
Mirrors do not provide a full view of everything behind you due to limitations like blind spots and field of vision. While they can reflect light and create an image that appears behind the mirror, they cannot capture areas outside their reflective scope.
Step-by-step explanation:
When backing up, mirrors do not give you a full view of everything behind you. Mirrors can only reflect light that reaches them, and are subject to limitations such as blind spots, the field of vision, and the way in which they are angled. To achieve a full-length reflection in a mirror, such as when we see ourselves, the mirror need not be as large as the person but must be positioned at an appropriate height and angle. Images in a plane mirror are the same size as the object, appear behind the mirror, and are upright. Objects appear to be behind the mirror due to the law of reflection, where the image formed is a virtual image, meaning light seems to diverge from a point behind the mirror. Nonetheless, a mirror cannot capture what is not directly in its reflective line of sight and peripheral vision remains unreflected. Hence, while backing up a vehicle, one must also use other methods, such as turning one's head or using additional mirrors, to obtain a comprehensive view.