Peoples Physics Concepts

14.2 Lorentz Force

14.2 Lorentz Force

• Describe the Lorentz force and how moving particles interact in a magnetic field.


• Solve various types of problems involving particles and magnetic fields using the Lorentz force and the right
  hand rule.

Students will learn about the Lorentz force and how moving particles interact in a magnetic field. In addition, the

right hand rule is covered. Students will also solve various types of problems involving particles and magnetic

fields using the Lorentz force and the right hand rule.

Key Equations

FB=qvBsinθ Force on a Charged Particle

where q is the charge of the particle, v is the velocity of the particle,Bis the magnetic field value andθis the angle
between the velocity vector and the magnetic field vector. Note that for problems where the direction of the particle
and the direction of the magnetic field are perpendicular then

FB=qvB

also, recall that

F=qE

E=V∆x for a constant electric field

Guidance

As moving charges create magnetic fields, so they experience forces from magnetic fields generated by other

materials. The magnitude of the force experienced by a particle traveling in a magnetic field depends on the charge

of the particle(q), the velocity of the particle(v), the strength of the field(B), and, importantly, the angle between

their relative directions(θ):

There is asecond right hand rulethat will show the direction of the force on a positive charge in a magnetic field:

point your index finger along the direction of the particle’s velocity. If your middle finger points along the

magnetic field, your thumb will point in the direction of the force. NOTE: For negative charge reverse the direction

of the force (or use your left hand)