Question

The L-shaped wire in the previous exercise (for Example 30.1) is now smoothed out with a quarter arc. In other words, the wire runs from y = +∞ to the point (0,b), then joined by a circular arc with radius b (centered at the point P(b,b)), continue on from (b,0) to x = +∞, with b = 0.4m. What is the magnetic field B (magnitude) at the point P(b,b) if the current is 2.0A?

I have no idea how to get started. What should be the first step?

Answer 1

Here is the L-shaped wire (attached)

Answer 2

vector S is an inversion of theta, but collinear.

Answer 3

orthogonal to b

Answer 4

run the conductance along x, until ring O...? Distribution of charge is proportional to material density and conductivity...i think.

Answer 5

one sec.

Answer 6

P(r)theta.. and a relation to ds

Let me grab a pencil

Answer 7

I see this problem and I would just like to let you know that I'm scared.

Answer 8

Um, I'm not following, but I do know this has something to do with the Biot-Savart Law.

Answer 9

The rotation is along one axis, point O. The conductance is along the vector (r).

At P(theta) it looks like the charge is then dispersed. As long as I is the rotation vector along with d(s)? I can't tell very well where the direction of vector s is pointing..

Answer 10

sSorry, Have to go back to work.

Answer 11

Alright, thanks for the help! But I still dont know how to get started T_T

Answer 12

start with seeing the rotation as a propagation point of a charge density, carried along the wire. Does that help?

Answer 13

The ring is spinning, if I'm not mistaken, and it looks like the vector (s) which is a magnitude is point orthogonal to (r). What do you know about orthogonal charges along a wire?

Answer 14

The drawing is poor, but if you try to find the wavelength of 2A along the wire, based on theta and rotations it might help.