# Magnetic fields and charged particles

• Sefrez
In summary, it has been stated that a charged particle in the vicinity of a magnetic field experiences a force given by F = qv x B, and that this force is only present when the particle has a non-zero velocity. However, if the frame of reference is changed to where the particle has zero velocity and the magnetic field is moving or changing, the kinetic energy of the particle can be changed due to the effects of Maxwell-Faraday's law and induction. This is because a time-varying magnetic field can create an electric field, as described by Faraday's law of induction. In this scenario, the force on the particle would be given by F=qE, and the use of F=qv×B would no longer
Sefrez
It has been stated that a charged particle in the vicinity of a magnetic field experiences a force given by F = qV x B, which states that there is no force when its velocity is zero. It also shows that only the particles direction can be changed, not its kinetic energy.

My question is this: what if you take the frame of reference that the particle has zero velocity and the magnetic field is moving (or changing)? Or simply, you have a stationary charge and pass a magnetic field by it?

In this context, is the kinetic energy of the particle then changed?

If so, is this at all related to, or the base idea of induction?

When you use F=qv×B this equation, v must be in reference to a non-changing B. If you want to use the reference frame in which the particle is the center of coordinates (ie. v=0), then you must use the induction laws, specifically:

E.dl = -(d/dt)∫∫B.dS, and F=qE

PS. It's so much easier to just use F=qv×B.

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## 1. What is a magnetic field?

A magnetic field is a region in space where a magnetic force can be detected. It is created by the movement of electrically charged particles, such as electrons, and is represented by lines of force that show the direction and strength of the magnetic field.

## 2. How do magnetic fields affect charged particles?

Magnetic fields can exert a force on charged particles, causing them to move in a circular or helical path. The direction of this force is perpendicular to both the direction of the particle's motion and the direction of the magnetic field.

## 3. What is the relationship between magnetic fields and electricity?

Magnetic fields and electricity are closely related, as they are both manifestations of the electromagnetic force. Moving electric charges create magnetic fields, and changing magnetic fields can induce an electric current.

## 4. How are magnetic fields and charged particles used in technology?

Magnetic fields and charged particles have various applications in technology, such as in generators, motors, and particle accelerators. They are also used in medical imaging techniques like MRI scans and in data storage devices like hard drives.

## 5. Can magnetic fields be harmful to humans?

In general, the magnetic fields encountered in everyday life are not harmful to humans. However, exposure to strong magnetic fields, such as those found in medical equipment or industrial settings, may have health effects. It is important to follow safety guidelines and limit exposure to strong magnetic fields.

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