1. Physics for Scientists and Engineers II, Summer Semester 2009 1 Lecture 25: July 27 th 2009 Physics for Scientists and Engineers II

2. Physics for Scientists and Engineers II, Summer Semester 2009 2 Image Formation by Refraction on Spherical Surface

3. Physics for Scientists and Engineers II, Summer Semester 2009 3 Image Formation by Refraction on Spherical Surface

4. Physics for Scientists and Engineers II, Summer Semester 2009 4 Magnification for Refraction on Spherical Surface

5. Physics for Scientists and Engineers II, Summer Semester 2009 5 Sign Conventions for Refracting Surfaces PositiveNegative Object Location (p)Real Object (in front of surface) Virtual Object (in the back of surface) Image Location (q)Real Image (in the back of surface) Virtual Image (in front of the surface) Image height (h’)Image is UprightImage is Inverted Radius (R)Center of curvature is in the back of surface Center of curvature is in front of surface Magnification (M)Image is UprightImage is Inverted

6. Physics for Scientists and Engineers II, Summer Semester 2009 6 Flat Refracting Surfaces Note: The sign of q is always opposite that of p  image and object are always on the same side for flat surfaces.

7. Physics for Scientists and Engineers II, Summer Semester 2009 7 Example: Flat Refracting Surfaces Problem 20 of Chapter 36: What is the apparent thickness of the glass plate when viewed from straight above the water?

8. Physics for Scientists and Engineers II, Summer Semester 2009 8 Example: Flat Refracting Surfaces Problem 20 of Chapter 36: What is the apparent thickness of the glass plate when viewed from straight above the water?

9. Physics for Scientists and Engineers II, Summer Semester 2009 9 Lenses A lens is basically an object with two refracting surfaces through which light passes. We start with two spherical surfaces having radii R1 and R2. How to calculate the image distance? Use the image created by surface 1 as the object for surface 2.

10. Physics for Scientists and Engineers II, Summer Semester 2009 10 Lenses ….and when the first image is real…..

11. Physics for Scientists and Engineers II, Summer Semester 2009 11 THIN Lenses

12. Physics for Scientists and Engineers II, Summer Semester 2009 12 Sign Conventions for Thin Lenses PositiveNegative Object Location (p)Real Object (in front of lens) Virtual Object (in the back of lens) Image Location (q)Real Image (in the back of lens) Virtual Image (in front of lens) Image height (h’)Image is UprightImage is Inverted Radii (R 1 and R 2 )Center of curvature is in the back of lens Center of curvature is in front of lens Focal length (f)A converging lensA diverging lens Note: Lenses always have TWO focal points (one for each direction of incident light).

13. Physics for Scientists and Engineers II, Summer Semester 2009 13 Ray Diagrams for Thin Lenses Incoming RayOutgoing Ray Parallel to Principal AxisThrough Focal Point F2 Through Focal Point F1Parallel to Principal Axis Through Center of LensGoes Straight Through

14. Physics for Scientists and Engineers II, Summer Semester 2009 14 Ray Diagrams for Thin Lenses Incoming RayOutgoing Ray Parallel to Principal AxisThrough Focal Point F2 Through Focal Point F1Parallel to Principal Axis Through Center of LensGoes Straight Through You need to trace outgoing rays back to where they seem to come from to find the virtual image location.