# Homework Help: Right Hand rule

1. Apr 24, 2010

### lha08

1. The problem statement, all variables and given/known data
I'm so confused about how to use the right hand rule..there are so many different sources telling me different things...like i need to use the RHR to like find the direction of the magnetic field using the current (and nothing else)..like i followed my book, and they said to use my thumb to point towards the current and wrap my fingers around the wire as if i was holding it in my hand, and the direction of the wrapped fingers would give the direction of the magnetic field, but everytime i do it for a question or something, even though the current is in the same direction, some questions tell me that the Magnetic field is in 2 complete different directions...like one will say the the M. field is out of the paper and the other into the paper even though the current is flowing in the exact some direction...help!!!

2. Relevant equations

3. The attempt at a solution

2. Apr 24, 2010

### Staff: Mentor

Last edited by a moderator: Apr 25, 2017
3. Apr 24, 2010

### lha08

But like when we solve problems, is there a specific way to use the RHR that will tell us if it's coming or going in the page at a specific current even though it moves in a circle?
Like when you said that when the current is moving from right to left, what do you mean by 'the magnetic field points into the page above wire and out of the page below it'...?

Last edited by a moderator: Apr 25, 2017
4. Apr 25, 2010

### Staff: Mentor

You use it just like you (and the link I gave) describe. Try to picture the magnetic field lines as circles in three dimensions surrounding the wire. The field always points tangent to the circle in the direction given by the RHR. Then you have to determine what direction the field points where it touches the page.
In that example, the wire is in the plane of the paper, so the magnetic field lines are circles perpendicular to the page. You must imagine how those field lines intersect the page. Where they touch the page above the wire, they are pointing directly into the page.