1. Answer the “4 big questions”.
Do Now:
Which ray of light will pass through “f” after it reflects through the mirror?
Answer the “4 big questions”.
If I double the mirrors center of curvature, what happens to the focus? C f

2. Aim: How does light interact with a convex and concave lens?

3. Convex lenses When light interacted with a mirror, what happened?
How do you think this is different for a lens?
Unlike a mirror that reflects light, a lens will “refract” light!
This works from both directions, since both sides are symmetrical.

4. How are Lenses and mirrors used in a telescope?

5. Convex Lens Ray Diagram
Draw a ray through the focus, then parallel.
Draw a ray parallel, then through focus.
object C f f C
image
Real Image

6. Other situations Lets look at some other convex lens situations…
Beyond the center of curvature or 2f
At the Center of curvature or 2f.
Object at the focal point.
Object in front of the focal point.
* Keep in mind, our eye is on the side where a real image forms.

7. Concave Lens C f f C eye Image always between f and lens. Virtual
1. Draw a ray parallel, then diverging away in line with the focus.
eye C f f C
2. Draw a ray going through the lens center.
Image always between f and lens.
Virtual

8. Summary How many situations do we have for a convex lens?
How do we draw the ray coming from an object in front of a convex lens?
What kind of image always forms for a concave lens? Where?