Magnetic Field -- Some help with the right hand rule please

AI Thread Summary
The discussion focuses on applying the right-hand rule to determine the direction of the magnetic force on an electron moving in a magnetic field. The magnetic force calculated is 1.16 x 10^-14 N, with the magnetic field directed upwards and the electron's velocity directed north. The correct application of the right-hand rule involves pointing the thumb in the direction of the velocity (north) and fingers in the direction of the magnetic field (up), resulting in the palm facing east, indicating the force direction. The radius of the electron's circular path is calculated to be 1.4 x 10^-3 m, confirming that the magnetic force also acts toward the east. Understanding the vector nature of the Lorentz force and the negative charge of the electron is crucial for correctly applying the right-hand rule.
Mary1910
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Homework Statement



A magnetic field of 0.0200 T (up) is created in a region.

a) Find the initial magnetic force on an electron initially moving at 5.00 x 10^6 m/s (N) in the field.

b) What is the radius of the circular path? Make a sketch showing the path of the electron.

Homework Equations



F=qvB

r=mv / qB

The Attempt at a Solution


a)
I have already determined that a) is 1.16 x 10^-14 N, my question is how do I use the right hand rule to determine direction? Since the velocity is (N) I point my thumb north and since B is (up) I have been pointing my fingers upwards. Therefore my palm is pushing East. Is this correct?b)
I found that r=1.4 x 10^-3 m so the magnetic force for also be (East)??

Some help with the right hand rule, specifically to this question would be appreciated.
 
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Are you familiar with the vector version of the Lorentz force? That helps me keep the Right-Hand Rule straight. So "X" represents the vector cross product:

F = qV X B

So first of all, remember that this question is about an electron, so qV is negative, or in the opposite direction from V. Does that make sense?

Second, The way I use the cross product is to curl my fingers from the first term vector to the second term vector, and the resultant vector is in the direction of my thumb. So If I curl my fingers from the qV direction (which is which way?) to the B vector direction, which direction is my right thumb pointing in? :smile:
 
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