# Why Are Electrons & Protons Deflected in a Magnetic Field?

• denian
In summary, in a magnetic field, electrons and protons are deflected in opposite directions, with electrons being deflected more due to their lighter mass. This is due to the Lorentz force, which creates a transversal acceleration in the particle's motion. From the perspective of the particle, this can be explained in terms of Coulomb's law, while from an observer's perspective, it is a relativistic effect on the electric field.

#### denian

in a magnetic field, i know that electrons and protons are deflected in opposite direction. electrons are deflected more greater because electron are lighter than proton.

but, why are they deflected? i understand why it will be deflected if they are in electric field. but why they are deflected in a magnetic field.

Originally posted by denian
in a magnetic field, i know that electrons and protons are deflected in opposite direction. electrons are deflected more greater because electron are lighter than proton.
I guess you are assuming both particles are moving through the magnetic field at the same speed... because if you were assuming they had the same (kinetic) energy this would not be the case (same behavior)

but, why are they deflected? i understand why it will be deflected if they are in electric field. but why they are deflected in a magnetic field.
Well it depends on how far you want to go with the explanation: it is simply because of Lorentz force at the most basic level (F=qvxB) that creates an acceleration transversal to the both field direction and the particle's velocity. In turn this effect can be explained (at least in some cases) as a relativistic effect on the electric field as it is perceived by the particle in motion. In its rest reference frame there might be no magnetic field but the inertial observer would observe one and explain the transversal acceleration as due to it. From the particle's point of view no transversal acceleration would exist and everything would be explainable in terms of coulomb's law...

Hope this helps, Dario

thank you, dario.

## 1. Why are electrons and protons deflected in a magnetic field?

Electrons and protons are electrically charged particles. When they move through a magnetic field, they experience a magnetic force due to their charge. This force causes them to be deflected from their original path.

## 2. How does a magnetic field affect the motion of electrons and protons?

A magnetic field exerts a force on charged particles that are moving through it. This force is perpendicular to both the direction of motion and the direction of the magnetic field, causing the particles to be deflected in a circular or helical path.

## 3. Can electrons and protons ever move in a straight line through a magnetic field?

No, the magnetic force will always cause electrons and protons to be deflected. This is because the direction of the force is always perpendicular to the direction of motion, so the particles will continuously change direction as they move through the field.

## 4. Why do electrons and protons move in opposite directions when deflected in a magnetic field?

The direction of the magnetic force on a charged particle depends on the charge of the particle and the direction of the magnetic field. Electrons and protons have opposite charges, so they experience a force in opposite directions when moving through a magnetic field.

## 5. How does the strength of a magnetic field affect the deflection of electrons and protons?

The strength of the magnetic field directly affects the amount of deflection of electrons and protons. A stronger magnetic field will exert a greater force on the particles, causing them to be deflected more than in a weaker field.