A magnetic field deflects an electron beam, but work on the beam

In summary, a magnetic field interacts with charged particles in an electron beam, causing them to change direction due to the Lorentz force. The strength of the magnetic field directly affects the amount of deflection of the beam, and it does not affect the overall work on the beam which is determined by the electric field. A magnetic field can be used to control the direction of an electron beam by adjusting its strength and orientation. In electron microscopes, a magnetic field is used to focus the electron beam onto a sample and create high-resolution images.
  • #1
DevilDoc
5
0
A magnetic field deflects an electron beam, but it can not do any work on the beam. Why? :confused:
 
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  • #2
It does not change the kinetic energy, only the direction.

The gotcha is that kinetic energy is frame dependent, but this feature is probably not of primary interest to you at this point.
 
  • #3
Another way of saying what turin just said is that the magnetic force is always perpendicular to the electron's velocity: No work is done since there is no displacement in the direction of the force.
 
  • #4
thank you for the help. :)
 

1. How does a magnetic field deflect an electron beam?

A magnetic field interacts with the charged particles in an electron beam, causing them to experience a force and change direction. This force is known as the Lorentz force and is responsible for the deflection of the electron beam.

2. What is the relationship between the strength of the magnetic field and the deflection of the electron beam?

The strength of the magnetic field directly affects the amount of deflection of the electron beam. A stronger magnetic field will result in a greater deflection of the beam, while a weaker field will result in less deflection.

3. Why does a magnetic field deflect an electron beam but not affect the overall work on the beam?

The work on the electron beam is determined by the electric field, not the magnetic field. The magnetic field only deflects the beam, but does not change its overall energy or work.

4. Can a magnetic field be used to control the direction of an electron beam?

Yes, a magnetic field can be used to control the direction of an electron beam. By adjusting the strength and orientation of the magnetic field, scientists can manipulate the trajectory of the beam.

5. How is a magnetic field used in electron microscopes?

In electron microscopes, a magnetic field is used to control the path of the electron beam and focus it onto a sample. By adjusting the strength and direction of the magnetic field, the beam can be scanned over the sample to create an image with high resolution.

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