Final answer:
To properly adjust a rear view mirror, you should see the entire rear window view. Two mirrors at right angles allow you to see the back of your head. Directly viewing bright lights, like car headlights, should be avoided to prevent eye strain.
Step-by-step explanation:
When adjusting the inside rear view mirror, you should be able to see out of the back window of your car with a clear view of the road and traffic behind you. Ideally, the mirror should be adjusted so that it frames the entire rear window, with minimal visibility of the interior of your own vehicle. The mirror's position should not require you to move your head out of your normal driving position. Moreover, you should avoid looking directly at bright lights, such as the headlights on your car, to prevent eye damage.
To see the back of your head, you would need to devise an arrangement of mirrors. According to physics, the minimum number of mirrors needed for this task is two mirrors placed at right angles to each other, allowing you to see a reflection of a reflection. This concept does not project a real image that needs to be seen on a screen, but rather a virtual image that appears behind the mirrors, in the direction the rays are coming from when they enter the eyes.