1. Lenses
and
Ray Diagrams

2. LENS: A shaped piece of glass or other transparent material with at least one curved side that causes light to refract.
There are 2 types of lenses:
1) CONVERGING LENSES – have 1 or 2 convex surfaces & are thicker in the centre than on the edges.

3. Converging lenses bring parallel light rays toward a common point.

4. There are 2 types of lenses:
2) DIVERGING LENSES – have 1 or 2 concave surfaces and are thinner in the centre than on the edges.

5. Diverging Lens spread parallel light rays away from a common point.

6. Converging Lens
Refraction in a Converging Lens always occurs at the Vertical axis (or Axis of Symmetry)

7. Refraction Rules for a Converging Lens 1
Refraction Rules for a Converging Lens 1. An incident ray which passes through the center of the lens will in effect continue in the same direction that it had when it entered the lens.
2. Any incident ray travelling parallel to the principal axis of a converging lens will refract through the lens and travel through the focal point on the opposite side of the lens regardless of size of curvature.
3. Any incident ray travelling through the focal point on the way to the lens will refract through the lens and travel parallel to the principal axis.

8. Use any of these 2 rules to construct a ray diagram
for converging lenses.

9. Summary of Ray Diagrams of Converging Lenses
Summary of Ray Diagrams of Converging Lenses ** If the image is located on the OPPOSITE side of the object, it is REAL. If the image is located on the SAME side of the object, it is VIRTUAL.

10. Refraction Rules for a Diverging Lens
RAY 1 F F
1. Any incident ray travelling parallel to the principal axis of a diverging lens will refract through the lens and travel in line with the focal point on the object side (i.e. its extension will pass through the focal point on the object side).

11. Refraction Rules for a Diverging Lens
2. An incident ray which passes through the center of the lens will in effect continue in the same direction that it had when it entered the lens.

12. Diverging lens
RAY 2 F F
3. Any incident ray travelling towards the focal point on the opposite side of the diverging lens (i.e. virtual extension) will refract through the lens and travel parallel to the principal axis.

13. Diverging lens SummaryF F