Section 4: Mirrors

Light waves spread in all directions from a light.  A mirror is a smooth surface that reflects light to form images.  There are three types of mirrors.  A plane mirror is flat and smooth.  When you look in a plane mirror, your reflection appears upright.  A concave mirror is when the mirror surface is curved inward.  The image depends on the location of the object relative to the focal point, which is the point at which light rays are reflected.  The focal length is the distance from the mirror’s center to the focal point.   A convex mirror is when the mirror is curved outward.  Light rays that hit these mirrors spread apart after they are reflected.  As a result, the reflected image is always upright and smaller than the actual object.  Objects in a convex mirror also look farther away than they are.

Mirrors can create both virtual and real images.  A virtual image is an image of an object that cannot be focused, whereas a real image is an image that can be focused.  Both plane mirrors and convex mirrors create virtual images.  In addition, mirrors that have curved surfaces, like a concave mirror, can be used to create real images.



  1. Define mirror.
  2. Identify the three types of mirrors.
  3. What’s the difference between a real and a virtual image?

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