1. Lenses and Image

2. Converging Lenses Terminology
Optical centre
Principal axis
Principal focus
(side of refracted rays)
Secondary principal focus
(side of incident rays)

3. Rules For Converging Lenses
Any incident ray parallel to principal axis of a converging lens refracts through lens and through principal focus on opposite side
Any incident ray traveling through primary focus will refract through lens and travel parallel to the principal axis
An incident ray passing through optical center will continue in same direction

4. Image Formation by Converging Lens

5. Images in a Converging Lens
OBJECT
IMAGE
Location
Size
Attitude
Type
Beyond 2F’
Smaller
Inverted
Between 2F and F
Real
At 2F’
Same size
At 2F
Between 2F’ and F’
Larger
Beyond 2F
At F’
No clear image
Inside F’
larger
Upright
Same side as object
virtual

6. Diverging Lens

7. Rules For Diverging Lenses
Any incident ray traveling parallel to principal axis will refract through lens and travel in line with the principal focus (i.e., extension will pass through focal point)
Any incident ray traveling towards principal focus will refract through lens and travel parallel to the principal axis.

8. Rules For Diverging Lenses
3. An incident ray which passes through optical centre will continue in same direction.

9. Diverging Lens Image Formation
Always Virtual, Smaller, and Right-Side Up