Recent content by auk411

(cosθ)2 using cos2θ. ... huh, what trig identity are you using. this still doesn't answer the most pressing question. t varies, theta varies and r varies. we have 3 varying variables in a DOUBLE integral. I see no way to reduce them to two. How do I get around this.

Someone who knows what they are talking about: Show what the magnitude of induced emf Homework Statement Consider a magnetic field B = K(x3z2,0, -x2z3)sinωt in the region of interest, where K and ω are positive constants and t is variable time. Show that the magnitude of the induced emf...

It would be most appreciated if you answer the questions that are asked. You answered how to solve it. I didn't ask that. I asked why mine was wrong. There are subtle differences. For example, I'm still confused by your answer because I'm not sure how (or if one can) integrate the following...

Here is the question: A very thin wire which follows a semicircular curve C of radius R,lies in the upper half of the x-y plane with its center atthe origin. There is a constant current I flowing counter clockwise, starting upward from the end of the wire on the positive x-axis and ending...

Homework Statement Two identical batteries of emf ε = 12 V and internal resistance r = 0.200 Ω are to be connected to an external resistance R, either in parallel or in series. If R = 2.00r Ω, what is the current i in the external resistance in the (a) parallel and (b) in the series...

I did and more responses are needed.

Thanks. But that still doesn't get to the heart of the matter. It turns out that we are adding (via the proffered equation) because the of the double negative, ie., we are subtracting and e is negative. Well, e is always going to be negative when talking about electrons. I assume that is why...

Homework Statement J = ne(v). (yes. it's a vector equation and I haven't indicated that, but just ignore that. It's not important to my question.) Let's say you have some positive ions traveling downward, and some negative ions traveling upward. The electric field is downward. Let's say...

Help much needed! Thanks!So this problem has been dealt with here on the physics forums. But the fact is that answers either appear to be false and/or they differ from what other people have done. First, here's the problem: In a certain region, the atmospheric electric field strength is 120...

How does this solution look good? I have plugged in these same numbers and you do not get the same number.

Ignore this. How does one delete a post?

Homework Statement If you have an infinite (non-conducting) sheet of uniform positive charge, except for a perfectly round hole in the middle, and you are trying to find the electric field above the circle, then is that the same as trying to find the electric field of the sheet with the...

Homework Statement Let's say you have a solid cylinder. It is nonconducting. It is long enough such that the contributions from the ends are negligible. It has a non-uniform volume charge density of Ar^2, where A is some positive constant. Then you are asked to find the electric field at...

Homework Statement Say you have a nonconducting spherical shell. A is the inner radius and B is the outer radius. If you wanted to set up an integral to find the flux, would the gaussian surface include B, or be just inside it? That is, would the limits of integration go from A to B? If...

"As you've written this field, I am interpreting it to mean that it has no z-component (the vector as written is two-dimensional), and so lies only in the xy-plane. This would mean that the field is only on one face of the box and does not enter it." I have no idea what you are trying to say...