# In which situation is the magnetic force nonzero?

1. Mar 23, 2012

### McAfee

1. The problem statement, all variables and given/known data
A particle moves through a magnetic field. In which situation is the magnetic force nonzero?

A. The charge is zero and the particle is moving perpendicular to the magnetic field.
B. The charge is negative and the particle is moving in the direction of the magnetic field.
C. The charge is zero and the particle is moving in the direction of the magnetic field.
D. The charge is zero and the particle is moving in the direction opposite that of the magnetic field.
E. The charge is positive and the particle is moving in the direction opposite that of the magnetic field.
F. The charge is positive and the particle is moving perpendicular to the magnetic field.

2. Relevant equations
F= qv x B

3. The attempt at a solution
I have ruled out A, C, and D. I think the answer is F because it will be equal to 1 then.

2. Mar 23, 2012

### tiny-tim

Hi McAfee!
Yes, that's correct

the others are 0 either because v is 0, or because v is parallel or anti-parallel to B (sinθ = 0)

3. Mar 23, 2012

### McAfee

Thanks tiny-tim for confirming and congrats on the 2011 PF Award. People like you are really helpful. I wish you best of luck in your future.