Magnetic Fields: Deciphering True/False Questions

[jazzylady03]

Magnetic Fields!

I have to choose which of these are true false. And they are really confusing me.

I know that the equation is F=qvB. However I am not sure what makes the problem different with constant velocity. Any help would be wonderful

Consider a charged particle moving with a constant velocity. Which of the following statements are true?
(Give ALL correct answers: B, AC, BCD.., or None)

A) The magnitude of the magnetic field generated by the charge is zero on the line of the moving charge.
B) The magnitude of the magnetic field generated by the charge is inversely proportional to the charge of the particle.
C) The magnitude of the magnetic field generated by the charge is inversely proportional to the speed of the particle.
D) The magnitude of the magnetic field generated by the charge is proportional to 1/r2 where r is the distance from the charge.
E) There is an electric field generated by the moving charge.

 

[Physics_wiz]

You're using the wrong equation. Try $$\v{B} = \mu q \v{v} \times \v{r} / (4\pi r^2)$$

 

[Graeme Robinson]

The correct answers are A and D.

A) True - The magnetic field is zero on the line of the moving charge because the particle is not experiencing a force in that direction.
B) False - The magnitude of the magnetic field is proportional to the charge of the particle, not inversely proportional.
C) False - The magnitude of the magnetic field is not affected by the speed of the particle.
D) True - The magnitude of the magnetic field is inversely proportional to the square of the distance from the charge.
E) False - The presence of a magnetic field does not necessarily mean there is also an electric field.