Curved Mirrors

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How to draw a ray diagram (p. 533-534)

For spherical mirrors, there are three different reference rays.

The intersection of any two rays locates the image

Slide 15

Rules for drawing reference rays (p. 534)

Slide 16

How to draw a ray diagram

Ray 1

Ray 2

The intersection

Of any 2 rays gives the image location

Slide 17

Objects inside the focal point

f

C

Slide 18

Sample Problem (p.536 #2)

A concave shaving mirror has a focal length of 33 cm. Calculate the image position of a cologne bottle placed in front of the mirror at a distance of 93 cm. Draw a ray diagram to confirm your results.

Slide 19

Draw the diagram

The image is inverted and about half the height of the object.

Slide 20

Convex Mirrors

Convex mirrors take objects in a large field of view and produce a small image

Side-view mirrors on cars are convex mirrors. That’s why they say “objects are closer than they appear”

Slide 21

Convex Spherical Mirrors (p. 537)

A convex spherical mirror (diverging mirror) is silvered so that light is reflected from the sphere’s outer, convex surface

The image distance is always negative!

The image is always a virtual image!

The focal length is negative !

Slide 22

Ray diagrams for convex mirrors

The focal point and center of curvature are behind the mirror’s surface

A virtual, upright image is formed behind the mirror

The magnification is always less than 1

Slide 23

Drawing the reference rays

Ray 1 is drawn parallel to the principal axis beginning at the top of the object. It reflects from the mirror along a line that intersects the focal point

Slide 24

Ray 2

Ray 2 starts from the top of the object and goes as though its going to intersect the focal point but it reflects parallel to the principal axis

Ray 1

f

C

Ray 2

Slide 25

Ray 3

Ray 3 starts at the top of the object and goes as though its going to intersect the center of curvature