1. Reflection of Light from Spherical Mirrors
Chapter 3
Reflection of Light from Spherical Mirrors

2. Concave and Convex Mirrors
The reflecting surface of a concave mirror “caves in” at the centre.
The reflecting surface of a convex mirror bulges out at the centre.

3. Describing Concave and Convex Mirrors

4. A ray strikes the pole of a concave mirror.
What is its path after reflection at the mirror?
It is reflected at an equal angle with the axis.

5. A ray which passes through the centre of curvature strikes a concave mirror.
What is its path after reflection at the mirror?
It is reflected back along its own path.

6. A ray which comes in parallel to the axis strikes a concave mirror.
What is its path after reflection at the mirror?
It passes through the focus after reflection.

7. A ray passes through the focus and then strikes a concave mirror.
What is its path after reflection at the mirror?
It is reflected out parallel to the axis.

8. What is a Real Image?
A Real Image is an image formed by the actual intersection of rays.
A real image can be formed on a screen.

9. Real Image in a Concave Mirror
After reflection at the mirror each of the rays from P passes through the same point X. A Real Image of P is formed at X.

10. A Real Image is formed in a Concave Mirror if the object is outside the focus.
A Real Image in a Concave Mirror is always:
Inverted.
In front of the mirror.

11. Real Image in a Concave Mirror

12. What is a Virtual Image?
A Virtual Image is an image formed by the Apparent Intersection of Rays.
A virtual image cannot be formed on a screen.

13. A Virtual Image is formed in a Concave Mirror if the object is inside (or on) the focus.
A Virtual Image in a Concave Mirror is always:
Upright (erect).
Magnified.
Behind the mirror.

14. Virtual Image in a Concave Mirror

15. Uses of a concave mirror
A dentist’s mirror.
Floodlights.
A projector.
A torch.
A cosmetics/shaving mirror.
A solar furnace.
A solar furnace used as a barbecue.

16. A Magnified Upright Virtual Image

17. A Concave Mirror being used in a floodlight
A Concave Mirror being used in a floodlight. The bulb is at or near the focus.

18. Formulae for a Concave Mirror
u is the distance from the object to the mirror.
v is the distance from the image to the mirror.
f is the focal length and m is the magnification
If the image is real:
If the image is virtual:

19. Convex Mirrors

20. A ray strikes the pole of a convex mirror.
What is its path after reflection at the mirror?
It is reflected at an equal angle with the axis.

21. A ray which is heading for the centre of curvature strikes a convex mirror.
What is its path after reflection at the mirror?
It is reflected back along its own path.

22. A ray which comes in parallel to the axis strikes a convex mirror.
What is its path after reflection at the mirror?
It is reflected as if it came from the focus.

23. A ray which is heading for the focus strikes a convex mirror.
What is its path after reflection at the mirror?
It is reflected out parallel to the axis.

24. Image formation in a Convex Mirror
After reflection at the mirror each of the rays from P appears to pass through the same point X. A Virtual Image of P is formed at X.

25. The Image in a Convex Mirror is always:
Virtual Diminished
Upright (erect) Behind the mirror

26. u is the distance from the v is the distance from the
Formulae for a Convex Mirror
u is the distance from the
object to the mirror.
v is the distance from the
image to the mirror.
f is the focal length
m is the magnification

27. A Convex Mirror gives a larger field of view than a Plane Mirror.

28. A convex mirror is used in a supermarket

29. A driving mirror is usually Convex

30. To measure the Focal Length ( f ) of a Concave Mirror