Textbook Reference 10.4 (P.431-434)

Convex (diverging) Mirrors

Convex MirrorsA mirror with a surface curved outward is a convex

mirror, also called a diverging mirrorA convex mirror spreads out the rays.

Uses for Convex MirrorsBecause convex mirrors allow you to see more than

plane mirrors, they are often used for security in stores as well as rear-view mirrors in cars.

Images Formed by Convex MirrorsAll images in a convex mirror are virtual. The reflected light rays never meet and the image

appears to come from behind the mirror.

Images in Convex MirrorsRules are similar to those for concave mirror except:

Focus is now called VIRTUAL FOCUSBoth F and C are behind the mirrorLight rays reflecting off a convex mirror diverge (this is why

a convex mirror is called a diverging mirror)Light rays seem to come from an apparent light source

behind the mirrorCreates virtual images

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Light Rays in a Convex MirrorsRULE: If the incident ray is parallel to the principal

axis, it will reflect as though coming from F.

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Light Rays in a Convex MirrorsRULE: If the incident ray is directed at the focus,

it will reflect as parallel to the principal axis.

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Light Rays in a Convex MirrorsRULE: If the incident ray is directed at the centre

of curvature, it will reflect straight back on itself.

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Steps to Locating Images in Convex Mirrors ... STEP 1Draw ray 1 from the top of the object.The incident ray parallel to the principal axis reflects

out, as if it came from the focus.Extend the reflected ray behind the mirror.

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Steps to Locating Images in Convex Mirrors ... STEP 2Draw ray 2 from the top of the object.The incident ray is aimed at the focus, and reflects

parallel to the principal axis.Extend the reflected ray behind the mirror.

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Steps to Locating Images in Convex Mirrors ... STEP 3Draw the image where the two rays converge to the

parallel axis.

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Steps to Locating Images in Convex Mirrors ... CHECKDraw the third ray to check the image.Incident and reflected rays go through the centre of

curvature. If it intersects, your drawing is correct.

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Point of intersection for all 3 rays

C

Properties of Images in Convex Mirrors

Image will always be:Size = SMALLER Attitude = UPRIGHTLocation = BEHIND THE MIRRORType = VIRTUAL

Convex mirrors are useful as security mirrors in stores and side-view mirrors on vehicles.

Some Uses for Convex & Concave Mirrors

CONVEX mirrors are useful as security mirrors in stores & side-view mirrors on vehicles.

CONCAVE mirrors are useful as flashlights, telescopes, car headlights, dental examination lights, and other applications.

HOMEWORK

TEXTBOOK P.434 Learning Check #1,3,4

WORKSHEET“Curved Mirror”