1. Reflection & Mirrors There are two kinds of mirrors Plane mirrors
Curved mirrors
Concave (Converging mirrors)
Convex (Diverging mirrors)

2. Images formed by plane mirrors

3. Characteristics of images formed by plane mirrors
Image size = object size
Image is virtual (not real; hence lines behind mirror are broken)
Image is upright (Erect)

4. Concave mirrors

5. Concave as converging mirrorF
Principle axis

6. The three rays of light
1. Ray parallel to the principle axis gets reflected through the Focal point 2 1
Principle axis C F
2. Ray through the Focal point gets reflected parallel to the principle axis. 3
3. Ray through C gets reflected alone the same path.

7. Images formed by concave mirrors
When Object is between mirror and F C F F C

8. Images formed by concave mirrors
When Object is at F C F F C

9. Images formed by concave mirrors
When Object is at C
gets reflected C F F C

10. Images formed by concave mirrors

11. Convex mirrors
Wide view

12. Convex mirrors
Diverges rays of light

13. Images formed by convex mirrors
Image Characteristics
Are virtual
Smaller
Behind the mirror

14. Images formed by convex mirrors
When Object is between c and F C F F C

15. magnification
We determine the magnification of the image using the formula;

16. The mirror formula

17. Image distance di

18. Homework
Textbook pg 460 # 1-7

19. Problem solving
Using the mirror formula

20. Example
Jose places an object 3 cm away from a concave mirror whose focal length is 10 cm. calculate the image distance.
1/f =1d0+1/di
1/10=1/3 + 1/di
1/di = 1/10-1/3
1/di = -7/10
di=-10/7= cm

21. Class work
Workbook Pg 175 # 5-8,
Workbook pg 180 # A-1 to A-5

22. Refraction of light
Refraction is the bending of a wave when one part of the same wave travels faster (or slower) than another part.
Pencil appear bent because of refraction
The waves are faster in air than in water causing our eyes to see the pencil that appear bent.

23. Refraction of light in glass
Light Bends when it passes the boundary line between two media

24. Refractive index (n)
Refractive index (n)  also called index of Refraction, is the measure of bending of a ray of light when passing from one medium into another.
Refractive index of any medium is given by the following formula:
Where speed of light in a vacuum C =3.0x108m/s

25. Refractive indices for different substances

26. Snell’s Law

27. Question
What is the speed of light in water?
(water; n=1.33)

28. Question
A beam of light that is traveling through air strikes flint glass at an angle of 30.0° to the normal. At what angle does the beam enter the flint glass? (Flint glass; n=1.656 and Air; n=1)

29. Total internal reflection

30. Total internal reflection
When total internal reflection takes place, the incident angle 1 is called the Critical angle c
Snell’s law becomes
n1sinc=n2sin 900

31. Homework
Textbook pg 461 # 11-21

32. Class work
Workbook pg 179 # 9-12, pg 180 # A6-A10