# Magnetic Field from Crossed Wires

1. Feb 23, 2009

### zooboodoo

1. The problem statement, all variables and given/known data
Two wires are both 22.3 meters in length and carry perpendicular currents as shown the the left. I1 = 4.5 A and I2 = 6.3 A. Points A and B are located an equal distance from both wires with d = 17 cm.
a) What strength of the magnetic field at A?
c) What strength of the magnetic field at B?

2. Relevant equations
SIGMA B DELTA L=MEWo * I
F = ILBSIN(theta)

3. The attempt at a solution
The problem gives the following 'help' features:
HELP: Use Ampere's Law
HELP: YOu can just add up the separate magnetic field strengths from both wires separately
HELP: Did you take into account the direction of the field from each wire?

I am having trouble relating equations that would take distance between the wire and the points (diagram at this link: https://wug-s.physics.uiuc.edu/cgi/cc/shell/DuPage/Phys1202/spring-evening/tma.pl?Ch-22-B-Fields/B_from_crossed_wires#pr [Broken] )
... I've tried to individually add the values for field strengths, (1.257e-6 * 4.5)/(22.3) + ((1.257e-6 * 6.3)/(22.3), I've also tried changing the signs in the different possibilities, any proper equations would be helpful, thanks.

Last edited by a moderator: May 4, 2017