Mirrors IIMirrors IIConcave Mirrors

Yesterday’s Review

0Law of reflection is: the angle of incidence is equal to the angle of reflection, or, θi = θr

0Plane mirror characteristics:0 Object size = image size0 Object distance = image distance0 Always forms a virtual image (the image cannot be

projected onto a screen)0 Image is reversed

Yesterday’s Review

0Plane mirror drawings:0 How did you draw the images in the plane mirror

from yesterday?0 Question 7 – How is it done?

Goals for the day

0Be able to draw a ray diagram for a concave mirror0Know the location & orientation (right side up or

upside down) of images in concave mirrors0Be able to communicate using appropriate

terminology such as: angle of incidence, angle of reflection, normal, centre of curvature, focus, & principal axis

Curved Mirror Terminology

0Center of curvature (C): the center of the circle where the mirror represents a small arc

0Focus (F): the point where parallel light rays converge; the focus is always found midway between the point where the principal axis cross the mirror

0Principal axis (PA): a line drawn through the center of curvature, the focus, and the mirror upon which the object rests

Characteristics of Concave Mirrors

0Concave mirror characteristics can differ depending on where the image is located in comparison to C and F

0L.O.S.T. can be used to remember what characteristics to look for:0 L is for relative location0 O is for orientation (upright or upside down)0 S is for the relative size of the image to the object

(bigger, smaller, or same size as the object)0 T is for type of image (either real or virtual)