Magnetostatics multiple choice

[goomer]

Homework Statement

A charged particle traveling with a velocity v in a magnetic field B experiences a force F that must be:

A. parallel to v
B. perpendicular to only v
C. parallel to v-B
D. parallel to B
E. perpendicular to v x B

Homework Equations

Requires this right hand rule, I believe:
http://upload.wikimedia.org/wikipedia/commons/6/6f/Right_Hand_Rule_vBF2.PNG

The Attempt at a Solution

Looking at the diagram, I'd say that the force should be perpendicular to both the force and the velocity and I had originally picked E. E is not correct, so would the right answer be B? But that would mean that force is not perpendicular to v and it very clearly is...

 

[collinsmark]

Homework Statement

A charged particle traveling with a velocity v in a magnetic field B experiences a force F that must be:

A. parallel to v
B. perpendicular to only v
C. parallel to v-B
D. parallel to B
E. perpendicular to v x B

Homework Equations

Requires this right hand rule, I believe:
http://upload.wikimedia.org/wikipedia/commons/6/6f/Right_Hand_Rule_vBF2.PNG

The Attempt at a Solution

Looking at the diagram, I'd say that the force should be perpendicular to both the force and the velocity and I had originally picked E. E is not correct, so would the right answer be B? But that would mean that force is not perpendicular to v and it very clearly is...

Are you sure you copied down the problem correctly? Including the choices? The answer isn't E, but it's not quite any of the other others either, as they're presently written.

 

[tiny-tim]

goomer, can you check the wording of C ?

 

[goomer]

goomer, can you check the wording of C ?

Oh sorry! C should be "Parallel to vxB".

I assume is C is the right answer then? If so, why?

 

[collinsmark]

Oh sorry! C should be "Parallel to vxB".

I assume is C is the right answer then? If so, why?

Maybe this will help.
http://en.wikipedia.org/wiki/Cross_product

 

[tiny-tim]

Looking at the diagram, I'd say that the force should be perpendicular to both the [field] and the velocity …

from the pf library …

The cross product of two vectors $\mathbf{A}$ and $\mathbf{B}$ is a third vector (strictly, a pseudovector or axial vector) $\mathbf{A}\times\mathbf{B}$ perpendicular to both of the original vectors … ​