- #1
lugita15
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I've been following the recent thread about work done by magnetic fields, and I'm more confused than ever. I have a few questions about the subject. I have phrased them as true/false statements.
Consider Statement A: If an object X moves in any direction which is not perpendicular to some force F, then the work done by F on X is nonzero.
Is Statement A true or false?
Consider the situation where there are two parallel current-carrying wires separated by some distance d, each having a current of magnitude I and pointing in the same direction. For simplicity, let us assume that the currents are going from the bottom of the page to the top of the page, and that the first wire is to the left of the second wire.
Now consider Statement B: By the Biot-Savart Law, the magnetic field due to the second wire at any point on the first wire is directed out of the page.
Is Statement B true or false?
Now consider Statement C: Since the magnetic force on a current-carrying wire is proportional to [tex]\vec{I}\times\vec{B}[/tex], by the right hand rule the magnetic force on the first wire due to the magnetic field of the second wire is directed to the right (that is, towards the second wire).
Is Statement C true or false?
Now consider Statement D: As a result of the rightward force it is experiencing, wire 1 will move to the right, i.e. closer to wire 2.
Is Statement D true or false?
Now consider Statement E: The direction in which wire 1 is moving, which is to the right, and the direction of the magnetic force acting on it, which is also the right, are parallel, which obviously means they are not perpendicular.
Is Statement E true or false?
Finally consider Statement F: Since wire 1 is moving in a direction which is not perpendicular to the magnetic force acting on it, by Statement A the work done by the magnetic force acting on wire 1 is nonzero.
Is Statement F true or false?
If you think that Statment F is false please point to the earlier step in which I made a mistake.
Any help would be greatly appreciated.
Thank You in Advance.
Consider Statement A: If an object X moves in any direction which is not perpendicular to some force F, then the work done by F on X is nonzero.
Is Statement A true or false?
Consider the situation where there are two parallel current-carrying wires separated by some distance d, each having a current of magnitude I and pointing in the same direction. For simplicity, let us assume that the currents are going from the bottom of the page to the top of the page, and that the first wire is to the left of the second wire.
Now consider Statement B: By the Biot-Savart Law, the magnetic field due to the second wire at any point on the first wire is directed out of the page.
Is Statement B true or false?
Now consider Statement C: Since the magnetic force on a current-carrying wire is proportional to [tex]\vec{I}\times\vec{B}[/tex], by the right hand rule the magnetic force on the first wire due to the magnetic field of the second wire is directed to the right (that is, towards the second wire).
Is Statement C true or false?
Now consider Statement D: As a result of the rightward force it is experiencing, wire 1 will move to the right, i.e. closer to wire 2.
Is Statement D true or false?
Now consider Statement E: The direction in which wire 1 is moving, which is to the right, and the direction of the magnetic force acting on it, which is also the right, are parallel, which obviously means they are not perpendicular.
Is Statement E true or false?
Finally consider Statement F: Since wire 1 is moving in a direction which is not perpendicular to the magnetic force acting on it, by Statement A the work done by the magnetic force acting on wire 1 is nonzero.
Is Statement F true or false?
If you think that Statment F is false please point to the earlier step in which I made a mistake.
Any help would be greatly appreciated.
Thank You in Advance.