# Magnetic field strength

## Homework Statement

I got 1/2 of this problem right, but I am not sure of the other part. I have attached the picture. The questions are as follows (with the answers that I am sure of) --

What is the magnetic field strength at point 1 in the figure?
What is the magnetic field direction at point 1 in the figure? (out of the page)
What is the magnetic field strength at point 2 in the figure?
What is the magnetic field direction at point 2 in the figure? (in to the page)
What is the magnetic field strength at point 3 in the figure?
What is the magnetic field direction at point 3 in the figure? (out of the page)

## Homework Equations

B = permeability constant * I/ 2(pi)r

## The Attempt at a Solution

Well, for the first one example, this is what I did.

(1.257*10e-6)*(10)/2(pi)(.02m) = 1*10e-4

This is not correct however? Can someone give me some instruction? And for the second and third ones, which wire am I calculating from?

#### Attachments

• 12.jpg
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