Review from last class – Complete Review from last class – Complete in your notes.in your notes.Review from last class – Complete Review from last class – Complete in your notes.in your notes.

1.A pinhole camera creates an image of a 37-meter-tall tree. If the image is 2.4 cm tall and inverted, what is the magnification of the camera?

2.Mirrors divert light using ______________, lenses divert light using ______________.

3.Describe the difference between specular and diffuse reflection.

Assignment 3/23 and3/24Assignment 3/23 and3/24

Turn in optical devices worksheet

Homework:

Read 20.3 and 20.4

Page 596, 1-13,

29, 30, 31, 52, 55,

Ray Diagrams Ray Diagrams (3/25 and 3/26)(3/25 and 3/26)

Mirrors

ReflectionReflectionReflection from a mirror:

Incident ray

Normal

Reflected ray

Angle of incidence

Angle of reflection

Mirror

The Law of ReflectionThe Law of Reflection

Angle of incidence = Angle of Angle of incidence = Angle of reflectionreflection

In other words, light gets reflected from a surface at THE SAME ANGLE it hits it.

The same !

!!

Flat MirrorsFlat Mirrors

Angle of incidence

Angle of reflection=

Normal

Flat MirrorsFlat Mirrors

If the rays leave the optical system and appear to come from some point in space, the point they appear to come from is a virtual image.

The converging reflected rays indicate the location of the image

Image DescriptionsImage Descriptions

How can we describe this image?

1.Is it upright or inverted?2.Is it magnified or unmagnified?3.Is it virtual or real?

Image DescriptionImage Description

This is an UPRIGHT, UNMAGNIFIED AND VIRTUAL image

Ray DiagramsRay Diagramsfor spherical mirrorsfor spherical mirrors

Rules for drawing a ray diagram:1. Draw an incident ray parallel to the principal axis, then

a reflected ray through the focal point2. Draw an incident ray through the focal point, then

parallel to the principal axis3. Draw a final line through the center point and back

along itself

Spherical Mirrors - Spherical Mirrors - ConcaveConcave

Image is REAL, INVERTED, and DEMAGNIFIED !!!

C F

Spherical Mirrors – ConcaveSpherical Mirrors – ConcaveObject Inside the Focal Object Inside the Focal

PointPoint

Image is VIRTUAL, UPRIGHT, and MAGNIFIED

C F

Spherical Mirrors - Spherical Mirrors - ConvexConvex

Image is VIRTUAL, UPRIGHT, and DEMAGNIFIED

C F

EquationsEquations

1/f = 1/do + 1/di

1/ focal length = 1/object distance + 1/image distance

m = - di/do

Magnification = - image distance / object distance

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