How does lorentz force work

The direction of the Lorentz force for a given direction of current and magnetic field can be remembered by the Right Hand Rule. If you took your right hand and stuck your thumb up, your forefinger first finger forward and your second finger perpendicular to the other two, then the direction of the force would be as indicated in the drawing below. The Right Hand Rule is supposed to help you remember which way things are pointing for the force on a moving charge. But personally, I think it is confusing.

Still, you should be aware of it, because some teachers include it in tests. The Lorentz Force is applied to an electric charge that moves through a magnetic field. It is perpendicular to the direction of the charge and the direction of the magnetic field.

Magnetic Force - HyperPhysics. We can combine the above equation with Eq. The equation of motion of a free particle of charge and mass moving in electric and magnetic fields is Figure Thompson's experiment. Let us analyze Thompson's experiment. Yes, a magnetic field affects electrons. Now, what specifically about this empirical fact would you like to ask about? Add a comment. Active Oldest Votes. Improve this answer. ProfRob ProfRob k 11 11 gold badges silver badges bronze badges.

Search engines revealed many more. HolgerFiedler HolgerFiedler 8, 4 4 gold badges 18 18 silver badges 54 54 bronze badges. To be honest I still couldn't get why the electron deflects in a magnetic field as said in this video. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. In other words, it is the radius of the circular motion of a charged particle in the presence of a uniform magnetic field.

If the velocity is not perpendicular to the magnetic field, then v is the component of the velocity perpendicular to the field. The component of the velocity parallel to the field is unaffected, since the magnetic force is zero for motion parallel to the field.

A particle experiencing circular motion due to a uniform magnetic field is termed to be in a cyclotron resonance. The term comes from the name of a cyclic particle accelerator called a cyclotron, showed in.

The cyclotron frequency or, equivalently, gyrofrequency is the number of cycles a particle completes around its circular circuit every second and can be found by solving for v above and substituting in the circulation frequency so that. Cyclotron : A French cyclotron, produced in Zurich, Switzerland in Helical motion results when the velocity vector is not perpendicular to the magnetic field vector.

In the section on circular motion we described the motion of a charged particle with the magnetic field vector aligned perpendicular to the velocity of the particle. In this case, the magnetic force is also perpendicular to the velocity and the magnetic field vector, of course at any given moment resulting in circular motion.

The speed and kinetic energy of the particle remain constant, but the direction is altered at each instant by the perpendicular magnetic force. What if the velocity is not perpendicular to the magnetic field? Then we consider only the component of v that is perpendicular to the field when making our calculations, so that the equations of motion become:. This produces helical motion i. The component of velocity parallel to the lines is unaffected, and so the charges spiral along the field lines.

If field strength increases in the direction of motion, the field will exert a force to slow the charges and even reverse their direction , forming a kind of magnetic mirror. Helical Motion and Magnetic Mirrors : When a charged particle moves along a magnetic field line into a region where the field becomes stronger, the particle experiences a force that reduces the component of velocity parallel to the field.

The motion of charged particles in magnetic fields are related to such different things as the Aurora Borealis or Aurora Australis northern and southern lights and particle accelerators.

Charged particles approaching magnetic field lines may get trapped in spiral orbits about the lines rather than crossing them , as seen above.

Those particles that approach middle latitudes must cross magnetic field lines, and many are prevented from penetrating the atmosphere. Cosmic rays are a component of background radiation; consequently, they give a higher radiation dose at the poles than at the equator.

Cyclotrons, magnetrons, and mass spectrometers represent practical technological applications of electromagnetic fields. Discuss application of mass spectrometers, movement of charged particles in a cyclotron, and how microwaves are generated in the cavity magnetron. Recall that the charged particles in a magnetic field will follow a circular or spiral path depending on the alignment of their velocity vector with the magnetic field vector. The consequences of such motion can have profoundly practical applications.

Many technologies are based on the motion of charged particles in electromagnetic fields. We will explore some of these, including the cyclotron and synchrotron, cavity magnetron, and mass spectrometer. A cyclotron is a type of particle accelerator in which charged particles accelerate outwards from the center along a spiral path. The particles are held to a spiral trajectory by a static magnetic field and accelerated by a rapidly varying radio frequency electric field.

Cyclotron Sketch : Sketch of a particle being accelerated in a cyclotron, and being ejected through a beamline. An additional static magnetic field is applied in perpendicular direction to the electrode plane, enabling particles to re-encounter the accelerating voltage many times at the same phase.

This frequency is given by equality of centripetal force and magnetic Lorentz force. The particles, injected near the center of the magnetic field, increase their kinetic energy only when recirculating through the gap between the electrodes; thus they travel outwards along a spiral path.

Their radius will increase until the particles hit a target at the perimeter of the vacuum chamber, or leave the cyclotron using a beam tube, enabling their use. The particles accelerated by the cyclotron can be used in particle therapy to treat some types of cancer. Additionally, cyclotrons are a good source of high-energy beams for nuclear physics experiments. A synchrotron is an improvement upon the cyclotron in which the guiding magnetic field bending the particles into a closed path is time-dependent, being synchronized to a particle beam of increasing kinetic energy.

The synchrotron is one of the first accelerator concepts that enable the construction of large-scale facilities, since bending, beam focusing and acceleration can be separated into different components. The cavity magnetron is a high-powered vacuum tube that generates microwaves using the interaction of a stream of electrons with a magnetic field.

All cavity magnetrons consist of a hot cathode with a high continuous or pulsed negative potential created by a high-voltage, direct-current power supply. The cathode is built into the center of an evacuated, lobed, circular chamber. A magnetic field parallel to the filament is imposed by a permanent magnet. The magnetic field causes the electrons, attracted to the relatively positive outer part of the chamber, to spiral outward in a circular path, a consequence of the Lorentz force.

Spaced around the rim of the chamber are cylindrical cavities. The cavities are open along their length and connect the common cavity space.