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14.2 Flat Mirrors. pp. 526 - 529 Mr. Richter. Agenda. Warm-Up Review HW Introduction to Reflection Notes: Reflection Law of Reflection Flat Mirror Images. Objectives: We Will Be Able To…. Distinguish between specular and diffuse reflection of light.
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14.2 Flat Mirrors pp. 526 - 529 Mr. Richter
Agenda • Warm-Up • Review HW • Introduction to Reflection • Notes: • Reflection • Law of Reflection • Flat Mirror Images
Objectives: We Will Be Able To… • Distinguish between specular and diffuse reflection of light. • Apply the law of reflection for flat mirrors. • Describe the nature of images formed by flat mirrors.
Warm-Up: • If the pencil in this picture is 2.5 inches away from the mirror, how far does the image of the pencil appear to be from the pencil itself?
Reflection • Light traveling in a uniform substance (air, water, etc.) will travel in a straight line… • Until it encounters a different substance (boundary). • When it hits the boundary, part of the light is absorbed, and part is sent off in another direction.
Reflection • This is calledreflection: the turning back of an electromagnetic wave at the surface of a substance. • A good mirror can reflect 90% of the incident (incoming) light.
Texture Surface affects Reflection • If a surface is smooth, all of the reflected light heads in the same direction. This is called specular reflection. • If a surface is rough, the reflected light heads in many different directions. This is called diffuse reflection.
The Law of Reflection: • If a surface is relatively smooth, the angle at which light strikes the surface is equal to the angle at which it leaves the surface. • In other words, the angle of incidence is equal to the angle of reflection. • θ=θ’
Mirror Images • When light from an object strikes a mirror, an image is formed. • This is a virtual image, meaning it cannot be projected onto another surface. • It only exists “inside” the mirror.
Mirror Images • The distance of the object from the mirror is equal to the distance of the image from the mirror. • Object distance = image distance. • The image appears to be the same size as the object.
Mirror Images • Images formed by a flat mirror appear to have a left-to-right reversal. • Leonardo da Vinci famously wrote with a mirror to make it harder for people to copy his notes.
Wrap-Up: Did we meet our objectives? • Distinguish between specular and diffuse reflection of light. • Apply the law of reflection for flat mirrors. • Describe the nature of images formed by flat mirrors.
Homework • p. 529 #1-6