All Questions
Tagged with magnetic-fields electrons
106
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Why is the speed of an electron constant in constant magnetic field?
I had known for long time that the magnetic Lorentz force $F= q \cdot (B \times v)$ acts on an electron so as to make it circle with this speed ($v$).
Recently I tried to imagine how this happens and ...
- 651
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2
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1k
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What direction is current for an electron in both $E$ and $B$ fields?
According to Fleming's left hand rule:
I am a bit confused however in the case of an electron travelling in a region of both electric and magnetic fields, which direction would the electric current ...
- 167
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votes
1
answer
91
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Does an electron change its energy when the spin projection is changed?
When an electron changes its spin projection in a magnetic field does it receive or take energy?
When the initial spin projection is indefinite (as is according to QM) how much is that energy?
- 651
3
votes
1
answer
63
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Why ray goes down when applied a magnetic force between it in the JJ Thompson experiment?
I have a question! I was learning about JJ Thomson's Cathode Ray Tube experiment and I understand why the ray goes up when it passes through a Wien's filter, but I cannot plenty understand why it goes ...
- 33
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1
answer
589
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Force on charged particle when moving along magnetic field lines
I was thinking, what happens to the force on a charged particle when it is moving along the magnetic field lines?
I am familiar with the right-hand-rule and it seems to me that RHR does not apply in ...
- 1,896
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2
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349
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Solenoid and induced electric fields
Let us suppose there is a solenoid which has $n$ turns per unit length the current is varying with time as $I =kt$ where k is a constant if the current is flowing then there must be induced electric ...
- 163
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46
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Why doesn't the magnetic field make electrons escape out of the material?
If a conducting rod moves within a magnetic field, the electrons within it will move for a short amount of time to create a potential difference. When the current is created within this rod, the rod ...
- 1,235
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1
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66
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Magnetic susceptibility of electron gas in non-uniform magnetic field?
Someone can explain briefly how to treat with perturbation theory a free electron gas in a sinusoidal external magnetic field ? I'm trying to understand the paramagnetic response of an electron gas to ...
- 1
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1
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188
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Is the electron spin $g$-factor value implying the particle is a composite one?
As I understood the highest possible value for a magnetic moment of a point charge having the same amount of charge as an electron and rotating with same electron velocity and confined in the same ...
- 2,255
4
votes
3
answers
2k
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The motion of an electron accelerating in a uniform magnetic field
As far as I know, when electrons travel perpendicular to a uniform magnetic field, the Lorentz force makes the electron undergo circular motion. As this electron undergoes circular motion, it emits EM ...
- 471
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415
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How do magnetic dipoles align with external magnetic fields?
Based on the equation for energy of a magnetic dipole in an external field:
$$E=-\mu \cdot B$$ I would have thought that the system would minimise its potential energy and so the $\mu $ will be ...
- 1,525
2
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43
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Eigenstates in a 2D metal disk with finite-size perpendicular magnetic field (Piece-wise Gauge)
Let's have a two-dimensional metal disk with radius R, and now I apply a uniform magnetic field B perpendicular to the disk, within the concentric part of the disk with radius r $\lt$ R. How can we ...
- 21
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votes
1
answer
146
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Working out the radial arc of a magnetic field to get mass of electron
We have an experimental setup as below, the magnetic field strength, Bq/30s, and distances (magnet distance, Geiger counter height, Geiger to magnet centre distance) have all been recorded. The energy ...
- 101
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1
answer
167
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Electrons direction in cathode ray tube
This image below show the movement of an electron in a magnetic field, it's taken from the video [Histoire des sciences] La découverte de l'électron explaining the experience of J.J. Thompson when he ...
- 101
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1
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The electric and magnetic field, reaching to infinity
I have difficulty’s to accept that the electric and magnetic field components of photons as well as of electrons and the other subatomic particles are extended to infinity. For practical use that does ...
- 10.6k