Answer:
c) 2
Explanation:
When a charged particle is moving in a region with a magnetic field, it experiences a force perpendicular to the direction of motion, therefore it starts moving with a circular motion.
The force experienced by the particle which is moving perpendicular to the field is given by
where
v is the speed of the particle
q is the charge of the particle
B is the strength of the magnetic field
Here we have:
- A proton, which has
(charge)
(speed of the proton)
B is the magnetic field
So the force experienced by the proton is
(1)
- An alpha particle, which has
(charge)
(speed of the alpha particle)
B is the magnetic field
So the force experienced by the alpha particle is
Here we are told that the force experienced by the two particles is the same, so:
And so we get:
Solving for the ratio between their speed, we find: