But this is not the way one normally uses spherical mirrors. Most of us have at one time or another used a spherical mirror as a magnifying device to view our faces for the purposes of shaving or applying makeup. See Figure 1. We will spend time in this activity examining this phenomenon and understanding how the image forms. Before you begin, recall the differences between real and virtual images.
Real images form when light from some optical instrument converges at a point or plane in space.
When you view a real image, your eye collects light that really came from the place where the image appears. Real images can be projected on to a screen. Virtual images form when light from some optical instrument seems to have left a point in space where the light never actually was present. Your eye collects the light from the instrument and the image is seen with definite size, shape and location, but the light did not really come from that location. Recall what you learned about the virtual image formed by a plane mirror.