Physics 360 Questions on the final
Question: In problem #3, you
forbid finding the B-field using current configuration.
Should I NOT use the Biot-Savart law? Should I find the
A? I understand if the second question cannot be answered, but I AM
concerned about the ambiguity of question #3. Thank you.
Answer: You are not to use any
RESULTS for any current configuration. For example, you are not
to look up the field due to a straight wire segment, which is done as
an example in both Griffiths and Lea and Burke, and use the
formula. Rather you are to calculate from first principles using
the Biot-Savart Law for a wire segment dl or a current j d(volume).
Question: In problem 4, can we
assume that the particle has a mass, m?
I noticed you stated "a uniform E-field...a large distance
the cylinder". I just assumed a uniform E-field throughout, even
around the location of the cylinder, or are we suppose to treat that
The field is uniform everywhere before the cylinder is put in
Afterward it remains unchanged a great distance from the cylinder, but
not necessarily anywhere else.
I was wondering if it's ok to reference our calculator for doing an
Only if you absolutely have to. The one integral you need to do is
pretty easy, actually. You "just" need the right substitution! But if
you run out of time and you still don't have it, use the calculator. A
calculator is just a small computer, so technically is forbidden by the
rules of the exam.
You won't get the points for doing the integral, but you will get the
points for the answer.