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

In summary, the conversation discusses the creation of a magnetic field in a region and the determination of the initial magnetic force and radius of a circular path on an electron moving within the field. The Lorentz force equation and the right hand rule are used to determine the direction of the force, with the result being towards the east. The vector version of the Lorentz force is also mentioned as a helpful tool for keeping the right hand rule straight.
  • #1
Mary1910
31
1

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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  • #2
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:
 

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

1. What is the right hand rule for magnetic fields?

The right hand rule is a method used to determine the direction of a magnetic field. It states that if you point your thumb in the direction of the current, the direction of your curled fingers will indicate the direction of the magnetic field.

2. How do you use the right hand rule to find the direction of a magnetic field?

To use the right hand rule, you first need to determine the direction of the current. Then, curl your fingers in the direction of the current. Your thumb will then point in the direction of the magnetic field.

3. What is the difference between the right hand rule for magnetic fields and the right hand rule for cross products?

The right hand rule for magnetic fields and the right hand rule for cross products both use the same concept of pointing your thumb in the direction of the current. However, the right hand rule for cross products is used to determine the direction of a vector resulting from the cross product of two other vectors.

4. Can the right hand rule be used for all types of magnetic fields?

Yes, the right hand rule can be used for all types of magnetic fields, including those created by electromagnets, permanent magnets, and even the Earth's magnetic field.

5. Are there any other methods for determining the direction of a magnetic field?

Yes, there are other methods for determining the direction of a magnetic field, such as using a compass or using the left hand rule. However, the right hand rule is the most commonly used method and is the most reliable for determining the direction of a magnetic field.

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