Plane Mirrors

The Laws of Reflection The angle of reflection always equals the angle of incidence The incident ray, normal, and reflected ray all lie in the same plane

Two Laws – Label the Diagrams

Regular and Diffuse Reflection regular reflection – the reflection of light off a smooth surface produces a clear reflection diffuse reflection – the reflection of light off a rough surface the reflection is not clear

The Characteristics of an Image “SALT” Size – larger, smaller , same Attitude – whether the image is upright or upside down Location – behind, in front or on the surface of the mirror Type – real or virtual real – light rays meet the image virtual – light rays do not meet the image EX. an image in a mirror

SALT - Size

SALT - Attitude

SALT - Location

SALT - Type

Constructing a Ray Diagram STEP 1 Draw an incident ray from the starting position on the image.

Constructing a Ray Diagram STEP 2 Draw the corresponding reflected ray

Constructing a Ray Diagram STEP 3 Extend the reflected ray behind the mirror using a dotted line.

Constructing a Ray Diagram STEP 4 Repeat steps 1-3 selecting a different incident ray from the same starting position. The point at which the two reflected rays intersect (cross) is the starting position for the reflected image. Draw this point.

Constructing a Ray Diagram STEP 5 Repeat steps 1-4 for the ending position of the image

Characteristics of Images in a Plane Mirror The image is upright. The image is the same size as the object. The image is virtual. The image is the same distance behind the mirror as the object is in front of the mirror.