convex mirrors lg: i can describe the uses on convex mirrors and draw ray diagrams involving convex...
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Convex Mirrors
LG: I can describe the uses on convex mirrors and draw ray diagrams involving convex mirrors
Curved Mirror Terminology
• Principal Axis – A straight line drawn through the centre of the mirror
• Vertex (V) – The point where the principal axis meets the mirror
• Focal point (F) – Where all reflected light rays converge
• Focal Length (f) – The distance from F to the mirror
• Centre of curvature (C) – The centre of the sphere to which the mirror belongs
• Radius of curvature (R) – Distance from C to the mirror
Convex Mirrors• A convex mirror is one that bulges
outward
• Where have you seen mirrors like this?
• Examine a convex mirror. How is the image different from the image in a plane mirror?
• Shine 5 beams of light at a convex mirror and explain where the light rays converge
Uses of Convex Mirrors
• Because convex mirrors produce small, virtual, upright images they are well suited for:– Security Mirrors– Rear View Mirrors
Ray Diagrams for Convex MirrorsAs with plane mirrors, we need to find the point where the reflected rays meet to determine where the image will beRules:1) Any light ray parallel to the principal axis will reflect as
though it is coming from the focal point2) Any ray that is directed
at the focal point, will be reflected parallel to the principal axis
3) Extend reflected rays backward to find image
F
Images in Convex Mirrors• Is the image closer or further from the mirror
than the object?
• Is the image upright or inverted?
• Is the image bigger or smaller than the object?
• Is the image real or virtual? Explain how you know.
Learning Check
• How does the focal point of a concave mirror differ from a convex mirror?
• If an object was placed at the focal point of a convex mirror, would you be able to see an image? Explain.
Ray Diagram Practice
• A convex mirror has a focal length of 5cm. An object 5 cm tall stands on the principal axis, 8 cm from the mirror. Use a ray diagram to determine the characteristics of the image:– Image distance– Image type (real or virtual; upright or inverted)– Image size
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