Moving charges in a magnetic field

1. Moving charges in a magnetic
field

2. Electron Beams
• The path of the electron
beam can be seen where
it over the fluorescent
screen in the tube. The
beam is deflected down-
wards when a magnetic
field is directed into the
plane of the screen.

3. Electron Beams (Continued)
• Each electron within the beam
experiences a force due to the magnetic
field.
• The beam follows a circular path because
the direction of the force on each electron
is perpendicular to the direction of motion
of the electron and to the field direction.

4. Calculating the Force
• A beam of charged particles crossing a
vacuum tube is an electric current across
a tube.
• F = BQv
(where F= the force of the particle
B= the flux density
Q= the charge of the particle
And v= the velocity of the charged particle.)

5. The use of Magnetic Fields
• Magnetic Fields are used in particle physics
detectors in order to separate different charged
particles and to measure their momentum from
the curvature of the tracks they create.
• All charged particles which follow this curvature
path is acted upon by a force due to the field.
Positively charged particles (such as protons)
are pushed in the opposite direction to
negatively charged particles (such as electrons).

6. The use of Magnetic Fields
• Magnetic Fields are used in particle physics
detectors in order to separate different charged
particles and to measure their momentum from
the curvature of the tracks they create.
• All charged particles which follow this curvature
path is acted upon by a force due to the field.
Positively charged particles (such as protons)
are pushed in the opposite direction to
negatively charged particles (such as electrons).