Physics 785 Q&A

Date

Question

Answer
Dec 14 Pr 1: You may use any of Maxwell's equations in this problem.
Dec 13 Pr 1: Can it be assumed that the flow speed of a plasma v < < c? Yes
Dec 13 Is there any mutual inductance between the inductors? No
Dec 13Several people have asked what an "arm" of a circuit is. An arm runs between two junctions.
Oct 23 For problem 9, is the midpoint rule suitable for the numerical Analysis? I was considering using Simpson's rule, however computing the 4th derivatives for the error bound seemed extraneous for the functions we are approximating. I'm not sure what you mean by "the mid-point rule". Simpson's rule is fine, no 4th derivatives needed. Remember that we discussed in class how to determine numerically whether you have the accuracy that you need.

Sep 11 2011

I was  having trouble understanding what you are asking in question 14.a.).  You are asking for the steady state current?  But the voltage itself that you gave us is oscillating.  Do you want us to just figure out the current when V=Vo?

 When you close the switch in an AC-powered circuit, there will be an initial transient, and the circuit will finally settle down into an oscillating steady state. This is what we want. Since the solution in part (b) has a time dependence, we cannot be looking for the current at any one particular time.

Sep 4 2011

I am also not sure whether a hemisphere means half of a sphere plus the disk which close it or only the half sphere part.

You can tell what is meant if you read the question carefully.  It tells you where the flat side is. 

Sep 4 2011

For problem 25(b), do I have to calculate the integral directly or can I use  Stoke's theorem for evaluating the integral?

You should always use the most efficient method.