Question

Recall three things about acceleration: * a curved trajectory requires a (centripetal) acceleration * acceleration is a vector; it has a direction and a magnitude * the magnitude of the acceleration is a = F/ m Recall that a charged particle, moving at velocity v perpendicular to a magnetic field, experiences a transverse force F=qvB. Recall also that charged particles can be either positive or negative. Using pencil and paper, combine the two formulas above to obtain a formula for acceleration in terms of the charge, velocity, magnetic field, and mass. Using the information above: which of these are most important in affecting the curved trajectories of alpha particles, as compared to beta particles, when they are passed through a magnetic field? (choose two answers) the sign of the charge the charge-to-mass ratio the magnitude of their charge the mass of the particles 1. + -/1 points When particles emitted by a radioactive source pass through a magnetic field, it is found some have bent trajectories, as shown in the figure. Rays 1 and 3 are bent in opposite directions, which indicates that The particles in rays 1 and 3 have opposite signs for their charge The particles in rays 1 and 3 both have negative charge The particles in rays 1 and 3 both have positive charge source

Answer 1

1] We have centripetal force = magnetic force

mv^2/r = qvB

r = mv/qB

r = v/[B*charge to mass ratio]

second option is correct.

2] First option is correct, that have opposite signs,

as F = q v B, opposite signs of q causes centripetal force due to magnetic field in opposite direction