Negative values of magnetic fields strength obtained?

[Mohummed Kazmi]

Homework Statement

We were asked to use a Hall probe (in units of Guass) to measure the magnetic field strength in 0.5 cm increments away from a wire carrying 4 A of current. As we got further and further away from the wire our B value got smaller and smaller. Eventually they became negative! What does this mean? If I calculate a theoretical B value using the standard equation then how am i supposed to account for the negative value[/B]

Homework Equations

[/B]
Magnetic field strength equation for a wire = Permitting constant* current/2* pi* d

The Attempt at a Solution

 

[SammyS]

Homework Statement

We were asked to use a Hall probe (in units of Guass) to measure the magnetic field strength in 0.5 cm increments away from a wire carrying 4 A of current. As we got further and further away from the wire our B value got smaller and smaller. Eventually they became negative! What does this mean? If I calculate a theoretical B value using the standard equation then how am i supposed to account for the negative value[/B]

Homework Equations

[/B]
Magnetic field strength equation for a wire = Permitting constant* current/2* pi* d

The Attempt at a Solution

Hello Mohummed Kazmi. Welcome to PF !

What was the reading with no current?

How far away from the return current, or any other current was the probe?