Selected Feedback Week 4 .

While creating a transformer in the lab I started to wonder if using a magnet as the core would increase the voltage output and thus effectiveness. If so then why don't we use them in all transformers.  

Excellent question.  Yes and no… are magnets always pointing in the same direction?  And if so, how will this affect a transformer (which required changing of the magnetic field back and forth)?

As far as Tuesday help sessions go, I find the Thursday one far more helpful.  Most people in the class will not have questions by Tuesday, and may not be able to attend Friday's session.

Thursday help session was moved to Tuesday because that is during my lab and then I have class on Fridays untill 4 so that leaves me little Help Session Time. I would like if you could keep the Thursday help session and maybe keep the Tuesdays help session for those who cant make it on Thursdays. I understand that you cannot accomidate everyones scheudle but...those help sessions really do help and I would like to be able to keep going. 

Do you think it would be at all possible to move the help room sessions to tuesday and thursday as oppossed to tuesday and friday?

Okay… we’ll revisit this issue at the end of next week but I do want ya’ll to attempt the first part of the hw early in the week…

What type of material should we expect on this exam? Is it mostly from lecture or the readding?

Lecture / hw / lab.

Although I feel that HW3 has a lot of good material, I feel it is much to long.  A homework assignment of this length overwhelms students in my opinion.  In the end, I think students put less effort into solving the problems and more into getting the assignment done (right or wrong).  If you need to put this many questions in the homework, make fewer of them essay format.

I felt that the homework for this week was very good, but a little too long.

I feel that because I spent so much time on the homework that I was not able to spend as much time studing for the test.

Thanks for the feedback. Yes, I’m a bit concerned/ aware of this.  On the other hand, I expect folks to spend 4+ hrs / week of hw.  If ya’ll are apsnding much mor ethan this, let me know and we can reassess. 

I’ll might simplify hw but still want ya’ll doing essays.

Notably the exams and hw will be on the same material… plus I value the HW’s (collectively) more than the exams.

Maybe it was just me, but I felt that the wording of the homework this week was sort of confusing.

On problem three of the homework in homework three the wording flips fr

Good suggestions.. I’ll be more clear in the future -- always feel free to clarify questions with me or TA's

I really like how you let us correct one question from the homework from the week before.

Cool we’ll do more of this.

i enjoyed the in-class experiments this week. along with the lab, they really helped to understand the concepts covered. i also like the candy incentive, it gives me a reason to give an answer even if it's wrong.   

Cool

With a transformer, I understand that a stun gun uses this to transfer the 9 volt battery power to anywhere from 100,000 to 500,000 volts, But how does it keep the current down to levels where it wont kill you, only jolt you or stun you for a period of time.  How do these things control the amount of current

Great question. Two things: 1) batteries are rated in amp-hours.. (basically how many electrons it can push around).. total charge… so it can push hard but only for a short time.  2) from V=IR we know that the resistance determines the amount of current Voltage produces.  For all batteries there is INTERNAL resistance, which limits the amount of current that can put out.

The one thing that I found confusing this week was determining the power going into the hair dryer and the light bulb given the voltage drop across the plugs. I tried everything but can't seem to get a resonable number.

Good question… come to office hours / help room.