I don't get how both wires can enter from the left and leave on the right unless either
(1) the circular part consists of 1 1/2 loops in both cases, or
(2) after making one loop and returning to the left end, both wires bend to leave at the right, following a diameter of the circle.
In either case, only the direction of the field at the middle should be different.
I'm sorry I can't help you with this. Maybe someone else can.
I must me missing something that would require seeing the figure to understand.
Consider the current-carrying wires in the figure.
I can try to describe the figure here..
- Diagram A has the wire coming from the left, it forms a loop in the centre in a clockwise direction and leaves going to the right.
- Diagram B has the wire also coming from the left, it forms a loop in the centre counter- clockwise and leaves going to the right as well.
Both cases consist of long straight wires carrying a current I.
In both cases, the wire is also bent in the shape of a circular loop of radius R.
The only difference is in how the bending of the wire is done to create the loop.
We are interested in the magnitude of the net magnetic field at the center of the loop.
If BA and BB are the magnitudes of the net magnetic fields at the center of each loop respectively, then which of the following statements is true?
a) BA < BB
b) BA = BB
c) BA > BB
d) There is not enough information to compare BA and BB
I guessed that both their magnitudes would be equal because the current and radius of both are equal; the only difference would be the direction of the magnetic fields, but this thinking is wrong..
5 answers
The answer 'B' is wrong?
But the only difference is direction of field.
But the only difference is direction of field.
I don't know if this might help to visualize: A's loop follows the way the greek letter gamma makes a loop, while B 's loop is in the shape of an upside down omega( Ω )...
wire A looks like
------o---
(consider that 'o' part is a continuous loop and -- represents wire))
wire B looks like
----(inverted omega, as sandra mentioned)---
i think Ba > Bb because in wire b there are some points where current changes direction and megnetic field is is reversed.
------o---
(consider that 'o' part is a continuous loop and -- represents wire))
wire B looks like
----(inverted omega, as sandra mentioned)---
i think Ba > Bb because in wire b there are some points where current changes direction and megnetic field is is reversed.
OK, I get it now. The straight parts of the incoming and outgoing wire are tangent to the loop. There IS a big difference in the field at the middle of the loop.
The higher B field is obtained at the middle in the "gamma loop" case because the B field produced by the straight sections of wires at the center of the loop is in the same direction as the field produced by the loop itself. In the other ("omega") case, they oppose each other at the center of the loop.
The higher B field is obtained at the middle in the "gamma loop" case because the B field produced by the straight sections of wires at the center of the loop is in the same direction as the field produced by the loop itself. In the other ("omega") case, they oppose each other at the center of the loop.
3 answers