Finn Ravndal has written a note on the magnetic field from solenoids. In this note Finn explains how to calculate the field at different points in space around and inside the solenoid. This can come in very handy for those of you who still feel a bit unfamiliar with the concept and for those who want to learn a bit more.
Here is the midterm exam with and without the solution.
I guess you are pretty exhausted after the midterm exam this week and a lot of you have probably had other exams to deal with as well. What better time to share a game with you to put your minds at ease for a little while.
The game is called Nanoparticles and was written by me about half a year ago. It is based on Coulomb’s law with a few modifications and Newtonian physics. But instead of having you calculate anything, the game does it all for you in the background. You can download the game for Ubuntu, Linux, Windows and Nokia phones here (Mac and Android versions will be available sometime in the future):
Your mission is to make sure the positive particles you control does not crash into the negative ones. That would cause it to annihilate. To do this, you need to place out other positive and negative particles to keep your particle away for as long as possible.
The game is also open source, so if you’re interested in programming and C++, you can have a look at the source code too. More information about the game and how to obtain the source code is found here.
Even though we’ve tried to keep the blog as updated as possible with the latest messages from the course pages, there have been a few that has slipped through our radar. To avoid this, we’ve added an automatically updated list to the front page of this website:
Under the heading “Latest messages” you’ll find the three latest messages that has been posted, and by clicking the link you’ll find all messages ever posted on the course pages. So keep an eye on this list in addition to the blog. Not all messages here will be posted in the blog from now on.
For instance, the following messages have not been posted here yet, and might be useful:
You may now sign up for the lab by writing your name on the list on the door to room V225.
The lab is held during week 45, 46 and 47 at the following times:
Monday and Tuesday: 08 – 12
Wednesday, Thursday and Friday: 13 – 17
Find a time that suits you and sign up on the list. The lab will be pretty much like how it was last year, and you can find this years experiments under the title “Lab-øvelser”:
http://www.uio.no/studier/emner/matnat/fys/FYS1120/h11/
We strongly encourage you to read through the lab exercises before coming to the lab. This way you will get much more out of the exercises and will hopefully understand a lot more of what the experiments actually teach us.
Due to the upcoming midterm exam there will not be held any lectures this week. The group on Friday will be closed, but the group/computer lab on Tuesday will be held as usual.
There came in some questions regarding the relevance of the weekly exercises considering the upcoming midterm exam. The answer is that the weekly exercises of course are relevant and therefore valuable practice. The questions for the exam might include everything that has been lectured up to and including the lecture 04.10 where the main subjects will be electrostatics, currents and magnetostatics. The lecture plan for the semester is found here:
http://www.uio.no/studier/emner/matnat/fys/FYS1120/h11/undervisningsplan.xml
Remember that you can bring an A4-paper with your own notes and allowed mathematical and physics tables (Rottman, Angell/Øgrim og Lian) as well as an approved calculator.
Update: There will be group lessons on Tuesday, 11 October, but no group lessons on Friday, 14 October.
The following exercises are subject for the next week’s plenumsregning:
1.2c, 2.3, 3.2, 3.5, 4.3, 4.5, 5.2
Jørgen will start with these next week and continue the following weeks.
As Finn mentioned in today’s lecture, there has been some information missing from the oblig:
The side walls in the well are made of conducting material.
Some of you have already been able to deduce this from that 
Good luck with the rest of the oblig, and remember to attend to the group sessions if you have any questions. If you don’t have the time to attend, you can of course contact us by e-mail or here on the web pages.
There are probably going to be a few things to watch out for in the oblig. One of these is characters not being copied correctly from the source code in the note on Jacobi’s method. A common error that Python will spew out in this case is
SyntaxError: Non-ASCII character '\xe2' in file ... on line 40, but no decoding declared ...
This is caused by the apostrophe ‘ being incorrectly replaced as a quotation mark ` during copying. The difference is very subtle, but for Python there is a huge difference; The apostrophe is completely legal to indicate a text string. The quotation mark is not.
The solution is to replace the offending quotation marks with apostrophes (the latter is found on the *-button on Norwegian keyboards) or to simply copy the source code manually instead.
Also, do watch out for whitespaces sneaking into your source code while copying.
Sadly, there is often many errors like these that show up when copying source code from PDF’s. Make sure you verify that the source code is the same after copying.