Lab for Thursday (18 Oct 07)

Here you go. Ac circuits and filters.

Basically, this is the stuff that makes your stereo work. Though the lab is couched in terms of the phase-shifted response in RC circuits, what we will really make is a low-pass filter, which is useful for separating the audio signals that should be sent to a woofer. A high-pass filter is what sends the signal to the tweeter. Hopefully, those last sentences will make sense by the end of Tuesday!

Also, by the end of Tuesday, you will see how a bunch of high-pass and low-pass filters together make an audio crossover, or equalizer.

So, if physics hasn't seemed useful yet, by the end of this week it will at least explain how your stereo works. This lab goes to eleven.

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I'm feeling generous. Three bonus homework points for the first person to leave a comment identifying the movie referenced in the above post. Just leave your name and the name of the appropriate movie in a comment to this post ...

Paper details

As I have mentioned a few times before, you have a 5 page paper this semester.

It won't be too bad.

Here are the details, subject to change. You need to choose a source ... soon.

The Plan for this week (15-29 Oct 07)

Ok. Due to my absence for the last half of the week, we'll do things a bit differently this week.

Short-attention-span version: double lecture Tues, no lecture Thurs.

Detailed version:

(1) I am gone for a conference from 17 until 20 Oct

• accessible via email to an extent
• it is easier to alter the schedule than to find a sub

(2) on Tuesday 16 Oct:

• finish unit on induction
• start and finish and ac circuits unit (short)
• double lecture, no lab

(3) on Thursday 18 Oct:

• no lecture, only lab
• ac circuits lab
• short induction lab

(4) for Friday 19 Oct:

• next homework set due (already assigned)
• covers (mostly) magnetic induction
• quiz covering magnetism and induction

(5) During the last half of the week

• you are responsible for reading the section on EM waves!
• it is not difficult, but we may not get to it in class
• it will, however, `be on the test'
• in the course notes or the Serway book

(6) Starting next week: optics

• for better or worse, we will be mostly done with E&M

Mid-term grades / My absence next week

Your mid-term grades will be posted tomorrow. As mentioned earlier, for the first time I must post grades for all students in 100 level courses, not just freshman. Sorry! To a large degree, your grade will be dominated by your score on Exam I. See the course information for information on what everything is worth. Ask me during the lab period tomorrow or afterward if you are curious about your grade to date.

And, FYI, I will be out of town (at a conference) from the afternoon of 16 Oct until 20 Oct, though I will be accessible by email. This means I will miss the class on 18 Oct, in which you will learn all about EM waves and start with optics. In my absence, there will be a lab as usual, and the lecture will be given by one of my colleagues.

Lab procedure 9 Oct 2007

Here you are.

This one should work fairly well, or at least it just did for me.

A few bits of advice:

• familiarize yourself with the function generator and voltmeter
• ask for assistance right away if you are not sure what everything does
• make sure you know the difference between the "primary" and "pickup" coils
• always, always be careful which units you use
  

Lab procedure 4 Oct 2007

Thursday's lab will be verifying Ampere's law, which you will be formally introduced to today.

You can find the procedure here.

This lab worked quite well for me this evening, but it has the potential to be time-consuming if you don't work carefully and follow the right procedure. Ask a question if you are in any doubt. Focus on taking all the data you need first, and then analyze your data. Even better, while some team members are measuring, the others can be plotting and calculating.

If you do not finish on time, you will be permitted to complete the report on your own time and turn it in during recitation. If you work efficiently, however, I think you can finish it with time to spare.

Mid-term grades

Mid-term grades are due Wed, Oct 10th (next Wed). For better or worse, faculty are now to post mid-term grades for ALL students in 100- & 200-level classes ... not just 1st year students.

Your mid-term grade will include everything you have done through the end of this week - the exam, homework, quizzes, and labs. On Tuesday of next week (9th Oct), I will give you all a chance to see your grade at the moment, and make sure everything seems ok.

Make the extra-credit possibility all the more timely, I guess.