Atomic Spectra Lab today ...

Here is the procedure

It is a lengthy but good lab, so we will devote plenty of time to it.

This is almost certainly your last lab too, for what that's worth.

Homework & What's next

We are a bit out of sync on homework right now. Your latest assignment came out earlier today on WebAssign, and is due next Monday at midnight. It covers Ch. 27, Quantum Physics.

The good news is, of course, that there are very few homeworks left this semester ...

For the remaining weeks, we will cover Quantum, Nuclear, and Atomic physics. Time permitting, there will be one special lecture on a "current topic" related to research here at UA. Possibly during dead week.

Finally, exam III has been moved to the Thursday before dead week. I will entertain particularly compelling arguments for other dates.

Humor

Science is hard

Passed along by one of your classmates ...

For today's lab ...

We measure Planck's constant, roughly.

Procedure

READ THE PROCEDURE. Really.

Relativity exercises

There are a few sneaky things in these exercises. And, one outright error.

For number 10, Webassign simply has the wrong answers coded. So I will tell you the answer Webassign wants for part a is 316 s ... the real answer is more like 296 s. Part B we will cover in class on Thursday.

For number 4, you want to set up something like "mv = (0.97)(gamma)mv" if you are supposed to find the velocity for 3% error.

For number 6, keep in mind that you want the difference in velocities between the Enterprise and the Klingon ship, as observed from the Enterprise. One of the velocities you put into the relativistic velocity addition formula should be negative ...

Some of the other problems have subtleties, but nothing beyond what we covered in lecture or what you might find in the example problems. There will be time to field some questions in class on Thursday.

And, I hope to have the relativity notes online before week's end.

Homework

My bad, I mistyped the due date for the homework ... as a result, it came due last night and it should not have.

I just switched the due date to Monday evening to fix the problem. You all should be able to work on it now.

Relativity Links

Neat pictures and graphs

Einstein himself on the subject, a popular account.