Calculating Current and Magnetic Field of Wire: Magnetism Question Solution

[Boulderbison19]

Homework Statement

A compas needle points 20 degrees East of North outdoors. However, when it is placed 8cm to the east of a vertical wire inside a building, it points 55 degrees east of north. what is the magnitude and the direction of the current in the wire? the Earth's field is 5.0E-5 and is horizontal

Homework Equations

Sin=O/H Cos=A/H

B=UI/ 2(pi)R

The Attempt at a Solution

i solved for the horizontal and vertical components of the Earth's magnetic field and found the components for the x and y to be 4.56E-5 and 2.04E-5 respectively.

i am stuck on how to find the components for the magnetic field of the wire.

any help will be greatly appreciated

 

[mbrmbrg]

What do the magnetic field lines around a wire look like?

 

[Boulderbison19]

there is no diagram, that is all the information given about the problem. i copied the problem word for word out of the book.

 

[mbrmbrg]

You didn't cover magnetic field lines in class? The book doesn't cover them in the section preceding the problem?

 

[Boulderbison19]

it does, but it doesn't cover this type of question.