Using Mirrors to Form Images

Plane Mirrors A plane mirror is a smooth, flat mirror Reflected rays form an image that we see in the mirror. How is this image formed? Let’s imagine an object like a dog in front of a mirror….

How Plane Mirrors Form Images Light bounces off the dog in all directions Some of those rays strike the mirror The light that strikes the mirror reflects at the same angle The reflected rays that reach your eye appear to be coming from a point behind the mirror. Your brain interprets the pattern of light as an image of the dog coming from behind the mirror.

Image Size, Distance and Orientation An image in a plane mirror is the same size and appears to be the same distance from the mirror as the real object. However, left and right appear to be reversed by a plane mirror.

Concave Mirrors A concave mirror is a mirror that curves inwards (caves in). Concave mirrors also form images but the image is different due to the angle that light rays reflect.

Concave Mirrors Light rays that reflect off concave mirrors converge and meet at a single focal point. The image formed by a concave mirror depends on how far the object is from the focal point.

Images in Concave Mirrors How the image appears simply depends on how close the object is to the focal point: Object Image Far away small and upside down Closer larger and upside down Really close larger and right side up (b/w focal point and mirror)

Convex Mirrors A convex mirror is a mirror that curves outwards (like the back of a spoon!) Light rays that strike a convex mirror diverge (spread apart) The image formed is always upright but smaller than the real object

Images formed by Convex Mirrors Images always appear smaller in convex mirrors More objects can be seen Convex mirrors are used in stores for security and in cars to see other vehicles

Law of Reflection Still Applies The law of reflection still applies to curved mirrors. The angle of incidence = the angle of reflection Let’s take a look… Reflection & Concave Mirrors