mirrors plane and spherical. plane mirrors flat mirrors. which type of image? virtual we perceive...

Mirrors

Plane and Spherical

Plane Mirrors• Flat mirrors. Which type of image?

Virtual

We perceive the image at

point I where the ray

extensions intersect

Clifton Bluhm

Real Penny

Image of Penny

http://www.throwlikeagirl.net/archives/000040.html

http://www.waitingtimetoys.com/wallmodels.2/fun.mirror.html

Curved MirrorsCurved Mirrors

Curved Curved ReflectorsReflectors

Principle AxisPrinciple Axis

FocalFocalPointPoint

FocalFocalLength Length

(cm)(cm)

http://www.atnf.csiro.au/news/press/images/urumqi/urumqi_25m_telescope.jpg

http://www.windows.ucar.edu/earth/images/arecibo.jpg

Diameter = 305 m (1000 ft) Built = 1963Location = Puerto Rico

Arecibo Radio Telescope

Focal Length of a Spherical Mirror

2

Rf

R – Radius of Curvature

Ray Tracing

We will predict the image that will be formed

by a mirror or lens using ray tracing. We

typically care about three ‘special’ rays:

1. Two rays that go through the focal points

2. The ray that go through the center of the object

Spherical Mirrors and Ray Tracing

The focal point of a concave mirror

The focal point of a convex mirror

Slide 18-32

Three Sets of Special Rays for a Concave Mirror

Slide 18-33

A Real Image Formed by a Concave Mirror

Slide 18-34

Slide 18-35

Three Sets of Special Rays for a Convex Mirror

Slide 18-36

Ray Tracing for a Convex Mirror

Slide 18-37

Images and Mirrors

• Real images will form on the side of the mirror where the object is located

• Virtual images will form on the opposite side

The Thin-Lens Equation – This works for both mirrors and lenses

1

s

1

s

1

fThin-lens equation (also works for mirrors)

relating object and image distance to focal length

Slide 19-10

Sign Conventions for Lenses and Mirrors

Slide 19-11

Magnification

m hh

ss

Slide 18-26

A random place for this slide but it needs to go somewhere. The next slide shows the different values from this equation.

Ray Tracing: Virtual Images

Slide 18-27

Sample ProblemA convex mirror has a focal length of -10

cm. An object of 4 cm high is placed 20 cm

in front of the mirror.

1. Find the position and size of the image.

2. Describe the nature of the image.