Answer:
Explanation:
When a charged particle moves perpendicularly to a magnetic field, the force it experiences is:
where
q is the charge
v is its velocity
B is the strength of the magnetic field
Moreover, the force acts in a direction perpendicular to the motion of the charge, so it acts as a centripetal force; therefore we can write:
where
m is the mass of the particle
r is the radius of the orbit of the particle
The equation can be re-arranges as
where in this problem we have:
is the magnitude of the charge of the electron
is the strength of the magnetic field
The beam penetrates 3.45 mm into the field region: therefore, this is the radius of the orbit,
is the mass of the electron
So, the electron's speed is