A particle moves along a circle in a region of uniform magnetic field of magnitude B=4.0 mT. The
particle is either a proton or an electron. It experiences a magnetic force of magnitude 3.2x1015 N.
What are (a) the charge of the particle? (b) The particle speed? (c) The radius of the circle? And
(d) the period of motion?
My only question is how do I determine the charge of the particle?
The Attempt at a Solution
a) If I assume that the magnetic field is going into the page (×) and the Force on the particle is positive then q⋅v must also be positive ∴ The particle positively charged +1e.
I'm not entirely sure that this is correct. I don't know if it matters if I make the magnetic field go into or out of the page since B and Fb are both given to be positive. My choice of positive and negative axis would have to be in a way makes both F and B positive anyways.
b) FB=qvB => v = Fb/qB
c) FB=mv2/r => r=mv/qB
d) v=d/t => v=2πr/t => t=2πr/v