Images on a Plane Mirror

Using Light Rays to Locate an Image Light rays and the laws of reflection help determine how and where an image is formed in a plane mirror. REFLECTION is the bouncing back of light rays from a surface.

We all know that light travels in a straight line. When your eyes detect reflected light from plane mirrors, your brain projects the light rays back in a straight line.

Laws of Reflection- Review When a light ray is incident upon reflection surface, the angle of reflection is equal to the angle of incidence. Both angles are measured relative to the normal. The incident ray, reflected ray and normal all lie in the SAME plane. Normal Reflected ray Incident ray same angle

Types of Images Real Images- mirrors can produce images that can be projected on a screen. A real image is ALWAYS inverted and appears in front of the mirror.

Virtual Image- mirrors can also produce images that cannot be projected on a screen. A virtual image is ALWAYS upright and appears behind the mirror.

Types of Mirrors Plane Mirror- a flat mirror that reflects light rays in the same way that they approach the mirror. Concave Mirror- a converging mirror where light rays that strike the mirror surface are reflected so they converge or “come together”, at a point.

3. Convex Mirrors- a diverging mirror where light rays that strike the mirror surface are reflected so that they diverge, or “go apart” and they never come to a point.

S.A.L.T SALT is used to describe images formed by mirrors. S- Size: compared to original object is it same size, smaller or bigger? A- Attitude: which way the image is oriented compared to the original object (upright or inverted). L- Location: location of the image (in front or behind the mirror). T- Type: is the image a real image or virtual image?

PLANE MIRRORS Characteristics of a plane mirror image: Object size= Image Size Object distance from mirror= image distance from mirror Attitude (orientation) is ALWAYS upright ALWAYS forms a virtual image Image is reversed- left to right

The image in a plane mirror appears to be backwards compared to how we view the object directly. This is why the word on the front of an AMBULANCE is written backwards- so it can be read when seen in a rear-view mirror. AMBULANCE

Steps for drawing Plane Mirror Ray Diagrams: 1. A ray that strikes perpendicular to the mirror surface, reflects perpendicular to the mirror. The reflected ray is extended beyond the mirror. 2. A ray that strikes the mirror at any angle reflects so the angle of incidence equals the angle of reflection. The reflected ray is extended beyond the mirror.

Ray Diagram Using 2 Points: Perpendicular ray Reflected ray Incident ray