chapter 7 light and geometric optics. 7.2 curved mirrors

Chapter 7Light and Geometric

Optics

7.2 Curved Mirrors

Types of Curved Mirrors• The images of CURVED MIRRORS are much different than what

you are used to from a “regular,” plane mirrors • Curved mirrors can be used to form images that are larger or

smaller than the object.

Types of Curved Mirrors• The images of CURVED MIRRORS are much different than what

you are used to from a “regular,” plane mirrors • Curved mirrors can be used to form images that are larger or

smaller than the object.

Concave Mirrors Convex Mirrors

Types of Curved MirrorsConcave Mirrors • Used whenever a magnified

image of an object is needed• They can also produce inverted, small images• They produce “real images”• Real image = an image that can be projected onto a screen

Types of Curved Mirrors• The opposite of Concave Mirrors• They curve outwards in the opposite direction of Concave Mirrors• Produce smaller images• A wider angle of view • Always produce virtual images

Convex Mirrors

Concave (Converging) MirrorsImaginary line drawn through the

vertex (V)Perpendicular to the surface of the

mirrorSingle Point through which rays

parallel to PA will reflect

The distance between the Vertex and the Focal Point

Concave (Converging) MirrorsRepresents the centre of the

sphere from which the curved mirror was cut

Represents the distance from the centre of curvature to the mirror

surface

Where Will an Image Form?

•Ray 1 and Ray 2 = follow the Law of Reflection•Ray 3 = any ray travelling through F to the V will be reflected right back•

Where Will an Image Form?Step #1: Draw a ray from the top and bottom of an object parallel to the PA. Its reflection from the mirror must pass through the F

f = R/2

Where Will an Image Form?Step#2: Draw a ray from the top and bottom of an object that passes through the F Its reflection from the mirror must be parallel to the PA. All rays MUST CONVERGE at the Focal Point (F)

Where Will an Image Form?Step#2: Draw a ray from the top and bottom of an object that passes through the F Its reflection from the mirror must be parallel to the PA.All rays MUST CONVERGE at the Focal Point (F)

Characteristics of the Image

TYPE: real

ATTITUDE: inverted

MAGNIFICATION: smaller than the

object

POSITION: Closer to the mirror

Characteristics of the Image

TYPE: real

ATTITUDE: inverted

MAGNIFICATION: smaller than the object

POSITION: Closer to the mirror, between C

and F

real inverted smaller than the objectBetween C and F

real invertedSame size as the objectAt C

real inverted larger than the objectTo the left of C

The Concave Mirror as a Magnifier

TYPE: virtual

ATTITUDE: upright

MAGNIFICATION: larger than the object

POSITION: behind the mirror

When the object is between F and the mirror

The Mirror Equation

Can You Predict The Location Of An Image Formed By A Concave Mirror?

A concave spherical mirror has a focal length of 10.0 cm. Locate the image of a pencil that is placed upright 30.0 cm

from the mirror. Draw a ray diagram to confirm your answer.

Practice Problems 7.2.1 (all)