Law of Reflection θ(i) = θ(r) θ(i) θ(r) Describes the behavior of light after it strikes a smooth surface such as a mirror. Incident ray Beam of light striking a surface. Reflected ray Beam of light bouncing back after striking a surface. Normal Line drawn perpendicular to surface where the incident ray strikes, from which all angles are measured. Angle of incidence (θi) Angle measured from the incident ray and the normal. Angle of reflection (θR) Angle measured from the reflected ray and the normal. The law of reflection states that when a ray of light reflects off a surface, the angle of incidence is equal to the angle of reflection: θ(i) = θ(r) Normal Eye Object θ(i) θ(r) Reflected Ray Incident Ray Virtual Image

How to Draw a Ray Diagram (Plane Mirrors) Draw a ray from the base of the object perpendicular to the mirror. Extend this ray behind the mirror using a dashed line. Draw a ray from the top of the object perpendicular to the mirror. Extend this ray behind the mirror using a dashed line. Draw a ray from the top of the object to the point where the first ray meets the mirror. Draw the reflected ray according to the law of reflection. Extend the reflected ray behind the mirror using a dashed line until it intersects the ray from the top of the object. This is the top of the image . O Image O’ Object Reference line Mirror

More about images & plane mirrors… Each sight line can be traced backwards beyond the mirror. All sight lines intersect at the image location. The image is formed at the single point on the opposite side of the mirror from where all the light rays appear to have diverged. Viewer 1 Object Virtual Image Location Viewer 2 Viewer 3