1. Light in Curved Mirrors
SNC 2D – Nelson Page 496

2. Curved Mirrors
Curved mirrors are created when you make part of the surface of a sphere reflective.
Concave (converging) mirror - A mirror shaped like part of the surface of a sphere in which the INNER surface is reflective
Convex (diverging) mirror– A mirror shaped like a part of the surface of a sphere in which the OUTER surface is reflective

3. Key Terminology
Centre of Curvature (C) – The centre of the sphere whose surface has been used to make the mirror
Principal Axis (PA) – The line through the centre of curvature to the midpoint of the mirror
Vertex (V) – the point where the principal axis meets the mirror

4. More Terminology…
Focus (F) or focal point – When a light is shone parallel to the principal axis, it will reflect back through the FOCAL POINT. The focal point is the location where all reflected rays parallel to the principal axis will meet.
Converge – to meet at a common point

5. Concave Mirrors – Locating Images Write down the three (+1) rules for locating images formed by concave mirrors and illustrate these rules on the diagram below.
(1) A light ray parallel to the P.A. is reflected through the Focus.
(2) A ray through F will reflect parallel to the P.A.
(3) A light ray through C is reflected back onto itself
(4) A ray aimed at the vertex will follow the law of reflection (angle of incidence = angle or reflection)

6. Concave Mirrors – Locating Images Follow Steps 1, 2 and 3 to locate an images reflection in a curved mirror
Draw lines from the top of the object to determine where the image will be located.
(1) A light ray parallel to the P.A. is reflected through the Focus.
(2) A ray through F will reflect parallel to the P.A.
(3) A light ray through C is reflected back onto itself (in our diagram this will just be the bottom of the image or the P.A.) *you shouldn’t need to use this rule to draw the image.
The top of the object will be where the reflected rays converge. Draw the object.
Object

7. Concave Mirrors – Describing Images
Describe the image you have created using the SALT acronym for help. S
size
Smaller A
Attitude
inverted L
Location
Between C and F T
type
Real (could be on a screen)
Object

8. Concave Mirrors – Describing Images Nelson pg 497
You can use the imaging rules for a concave mirror to find the characteristics of images at a variety of object locations.
You do not need to memorize this, you can just draw 2 rays for an image to find out these characteristics for any image!
Object Location Beyond C

9. Concave Mirrors – Describing Images Nelson pg 497
You can use the imaging rules for a concave mirror to find the characteristics of images at a variety of object locations.
You do not need to memorize this, you can just draw 2 rays for an image to find out these characteristics for any image!
Object Location
at C

10. Concave Mirrors – Describing Images Nelson pg 497
You can use the imaging rules for a concave mirror to find the characteristics of images at a variety of object locations.
You do not need to memorize this, you can just draw 2 rays for an image to find out these characteristics for any image!
Object Location
In front of C

11. Concave Mirrors – Describing Images Nelson pg 497
You can use the imaging rules for a concave mirror to find the characteristics of images at a variety of object locations.
You do not need to memorize this, you can just draw 2 rays for an image to find out these characteristics for any image!
Object Location
At F

12. Concave Mirrors – Describing Images Nelson pg 497
You can use the imaging rules for a concave mirror to find the characteristics of images at a variety of object locations.
You do not need to memorize this, you can just draw 2 rays for an image to find out these characteristics for any image!
Object Location
Between F and mirror

13. Convex Mirrors – Locating Images Write down the two (+1) rules for locating images formed by concave mirrors and illustrate these rules on the diagram below.
(1) A ray parallel to the principal axis is reflected as if it has come through the focus
(2) a ray aimed at the focus is reflected parallel to the principal axis
(3) A light ray through C is reflected back onto itself F C

14. Convex Mirrors – Locating Images Write down the two (+1) rules for locating images formed by concave mirrors and illustrate these rules on the diagram below.
(1) A ray parallel to the principal axis is reflected as if it has come through the focus
(2) a ray aimed at the focus is reflected parallel to the principal axis
(3) A light ray through C is reflected back onto itself
Object F C

15. Convex Mirrors – Describing images
Describe the image you have created using the SALT acronym for help. S
Smaller
*a convex mirror always produces a smaller virtual image* A
upright L
Behind mirror T
Virtual (can not be on screen)
Object F C

16. REVIEW
A converging (concave) mirror has its focus on the same side as the object; a diverging (convex) mirror has its focus behind the mirror
A diverging (convex) mirror always produces a smaller, upright, virtual image
A real image can be seen if a screen is put in front of the mirror. A virtual image is one that appears behind the mirror and will not appear if a screen is placed behind mirror
Ray Diagrams
PARALELL  Through Focus
THROUGH FOCUS  Parallel
A light ray that is parallel to the principal axis of a curved mirror is reflected through the focus F
If the mirror is diverging (convex) parallel rays are reflected away from the virtual focus, which is behind the mirror
A least 2 incident rays are drawn to determine whether or not an image is formed
Incident rays should originate from the top of the object when drawing ray diagrams

17. PRACTICE Complete “Concave and Convex Mirrors Worksheet”
Questions page 501 # 2, 4, 8