Unit 2: Lesson 7 - Concave & Convex Mirrors

Real & Virtual Images

REAL

- Image made from ? that does what?

- What can you do with it?

- how does Light move?

- always? (its looks/orientation)

Virtual

- Cannot be?

- How does image appear?

Real

- Image made from "real" light rays

- that converge at a real focal point so the image is REAL

- Can be projected onto a screen

- light actually passes through the point where the image appears

- Always inverted

Virtual

- Not "Real" because it cannot be projected

- Image only seems to be there!

Virtual Images in Plane Mirrors

- If light energy doesn't flow

from the image, the image

is ?

How are rays behind the mirror?

- If light energy doesn't flow from the image, the image is "virtual".

- Rays seem to come from

behind the mirror, but, of

course, they don't.

- It is virtually as if the rays were

coming from behind the

mirror.

- As far as the eye-brain

system is concerned, the

effect is the same as would

occur if the mirror were

absent and the chess piece

were actually located at the

spot labeled "virtual image".

Plane mirrors

- The law of reflection states that?

- Using the law of reflection, we can determine?

- The law of reflection states that when a ray of light is reflected

from a surface,

- it is reflected in such a direction that the incident angle equals the reflected angle.

- Using the law of reflection, we can determine the location of images formed by plane mirrors.

Concave Mirror

- _____ mirror

- _______ light

- Curves?

- real or virtual image?

- The focal length (f) is _____ the radius of curvature (C).

- converging mirror

- converges (intersects) light

- Brings it together

- Curves inward

- May be real or virtual image

- The focal length (f) is half the radius of curvature (C).

- Convex mirror

- does what to light?

- Curves?

- images appear? (size)

- ___ images

- Use (eg): ?

- Diverging mirror

- Diverges (separates) light

- Spreads out

- Curves outward

- Reduces images

- Virtual images

Use: Rear view mirrors, store security...

In order to draw images formed by curved (concave) mirrors, remember that : (4)

1. A ray parallel to the principal

axis is reflected through the

focal point (F).

2. A ray that goes through the focal

point (F) is reflected parallel to the

principal axis.

3. A ray that goes through C

(the center of curvature) is reflected back

along its own path.

4. A ray that strikes the vertex (V) is

reflected like a plane mirror. (Angle of

incidence = Angle of reflection)

Optics Rules Summary (4)

Optics Rules Summary

1. If the incidence ray is parallel to the mirror

surface, the reflected ray will go through F.

2. If the incidence ray goes through F, the reflected ray will be parallel to the mirror surface.

3. If the incidence ray goes through C, the reflected ray will go back through C.

4. ANY OTHER incident ray will follow the rule

θr = θi

For convex mirrors, the image is ALWAYS: 4?

For convex mirrors, the image is ALWAYS:

1) VIRTUAL,

2) INSIDE the mirror,

3) UPRIGHT and

4) SMALLER than the object.

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