# Magnetic Fields

## Homework Statement

Two current carrying wires cross at right angles (like a + sign).

Wire 1 has current directed horizontally to the left. Wire 2 has current directed vertically up.

If the wires are not restrained, what statement best describes the motion of the wires?

A) Wire 1 moves out of the page; Wire 2 moves into the page
B) Wire 1 rotates clockwise; Wire 2 rotates counterclockwise
C) Wire 1 rotates counterclockwise; Wire 2 rotates clockwise
D) Wire 1 moves up; Wire 2 moves to the left
E) Wire 1 moves down; Wire 2 moves to the right

## The Attempt at a Solution

The wires will rotate until the magnetic fields are in the same direction. Therefore I think Wire 1 will move up and Wire 2 moves to the left.

Have I visualized it correctly?

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tiny-tim
Homework Helper
Hi 05holtel!

I think you're misunderstanding the terminology …

if wire 1 moves up and wire 2 moves to the left, then they're moving parallel to themselves, and the field directions won't change.

Oh Yeah,oops

Rotating Wire 1 clockwise and Wire 2 counterclockwise would make the magnetic fields go in the same direction. Correct?

tiny-tim
Homework Helper
Oh Yeah,oops

Rotating Wire 1 clockwise and Wire 2 counterclockwise would make the magnetic fields go in the same direction. Correct?
come on … you're just guessing aren't you?

Rotating Wire 2 clockwise and Wire 1 counterclockwise would also make the magnetic fields go in the same direction, wouldn't it?

So which one is correct, and why?

I am really confused still,

I know I have to draw first the magnetic field that Wire 1 makes at the points shown on Wire 2. Use those magnetic fields and the current of Wire 2 to find the forces on Wire 2. Repeat the same procedure for the magnetic field that Wire 2 makes at the points shown on Wire 1. Use this now to find the forces on Wire 2.

I am not getting any of the suggested solutions