Homework correction

Question 1e should read:  What is the WAVELENGTH of light in Lallium.

Sorry for the confusion.

Quiz answers

Getting started on the lab

To remind you:

After you have done both the lens and mirror parts of the lab, start to look at your data for trends:

Is there a point where images go from bigger to smaller, real to virtual, etc.?  Is this related to the approximate focal length (measured at the beginning of the trials?  Start to think and write about this.  Hint - there IS something to be seen, even if it's tough to tell from your data.

Check out this applet:

http://www.physics.metu.edu.tr/~bucurgat/ntnujava/Lens/lens_e.html

Move the object (arrow) and note what happens to the image.  Think about this as it relates to your lab.

Now - calculate experimental focal lengths with your data (for convex lenses and concave mirrors), using the mirror/lens equation.  Are these close to the approximate f (from outside)?  Start thinking about sources of error.

Your lab will have the following:

- data
- discussion of trends seen
- calculation of f -- show a sample calculation (don't show ALL calculations, though all f's need to be calculated)
- sources of error
- general conclusion

Be sure to talk about how different your calculated f's are from the approximate f that you got from focusing on something outside.

A couple questions to answer:

1.  How could one possibly determine the focal length of a convex mirror or concave lens?  Is it possible to experimentally determine?

2.  What should happen if you cover up part (or most) of the lens or mirror?  Do you still get images?  How are they affected?

Important

Please bring your physics notebook/notes/laptop to the next class -- I want to do a notes check while you take the quiz.  Thanks!

I'm NOT grading the notebook - I just want to get a sense of how (or if.....) you take notes.

Stuff for next class

Quiz (E):  Thursday
Quiz (A):  Friday

Quiz is on:  Snell's law, index of refraction, etc.  Possible question about focal length.  Possible practical part.

After you have done both the lens and mirror parts of the lab, start to look at your data for trends:

Is there a point where images go from bigger to smaller, real to virtual, etc.?  Is this related to the approximate focal length (measured at the beginning of the trials?  Start to think and write about this.  Hint - there IS something to be seen, even if it's tough to tell from your data.

Check out this applet:

http://www.physics.metu.edu.tr/~bucurgat/ntnujava/Lens/lens_e.html

Move the object (arrow) and note what happens to the image.  Think about this as it relates to your lab.

If you have time, start to calculate experimental focal lengths with your data (for convex lenses and concave mirrors), using the mirror/lens equation.  Are these close to the approximate f (from outside)?  Start thinking about sources of error.

quiz

A - quiz Friday
E - quiz Thursday

Topics:

Snell's law
- be able to use it (in all its forms) to find:  n, angle, wavelength, speed of wave

Index of refraction

focal length

There *may* be a practical component to the quiz.