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Concave and Convex Mirrors. Section 4.4 Lesson 9. Concave. Concave mirrors have a curved side where the reflective surface is on the “caved in” face of the mirror.
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Concave and Convex Mirrors Section 4.4 Lesson 9
Concave • Concave mirrors have a curved side where the reflective surface is on the “caved in” face of the mirror Think of a concave mirror as part of a section cut off from a sphere or ball with the reflective surface coating the inside of the ball. Describe the appearance of the image in this concave mirror
Uses of concave mirrors Light-house mirror Makeup mirror Dental mirror telescope
Vertex (v) – the point where the principal axis meets the mirror Concave mirror terms • Principal axis – a line drawn through the centre of the circle Principalaxis
Radius of Curvature – the distance from C to the mirror C Concave mirror terms • Centre of curvature (C) – the centre of the sphere that the mirror fits on
Principalaxis C F f Concave mirror terms • Focal point (F)– exactly halfway between the centre and the mirror Focal length (f) – the distance from F to the mirror
Concave mirror terms All light rays that hit the surface of the mirror are parallel to the principal axis and reflect back through the focalpoint
Drawing Ray diagrams to Locate Images • The type of image produced by a concave mirror will change depending on the location of the object • For example, if the object is: • Beyond C • Between C and F • Between F and the mirror • Each situation will create a different set of image characteristics
Step 1 Draw a straight line behind the mirror through the vertex Draw an incident ray parallel to the principal axis that reflects through the focal point
Original object C F
Step 2 • Draw an incident ray through the focal point that reflects parallel to the principal axis
C F
Step 3 • Draw an incident ray through the centre of curvature that will reflect straight back through the centre of curvature • Describe the characteristics of the image
C F inverted L: _____________ O: _____________ S: ___________ T: _________ closer smaller real
The results where the object is between the focus and the mirror
Notes • Complete the handout • 4.4 Concave Mirrors: Drawing Ray Diagrams to Locate and Draw Images
Vocabulary Journal • Add and define these terms • concave • convex • principal axis • centre of curvature • focal point (focus)