Beyond Lorentz Force: Electron Circles in Magnetic Field?

AI Thread Summary
When a wire is placed in a magnetic field, the Lorentz force acts on electrons, causing them to change direction without altering their speed. Free electrons can move in circular paths, but electrons in a wire are constrained to follow the wire's path. The discussion highlights the importance of understanding that while the direction of an electron's velocity changes, its speed remains constant. Misunderstandings about velocity and speed are clarified, emphasizing the need for precise terminology. Overall, the conversation reinforces the principles of electromagnetism and the behavior of electrons in magnetic fields.
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When a wire is placed in a magnetic field, Lorentz force acts on an electron in a direction perpendicular to velocity and to the magnetic field, since the magnetic force is perpendicular to the velocity the electron will only change direction with no velocity change, what happens after that, I have heard that the electron will move in circles, is that true??
 
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A free electron moves in circles (assuming the field spreads out wide enough to cover that), but electrons in a wire cannot just leave that, so they follow the wire.
 
We can say that if the force was not perpendicular to the velocity will have an ever-increasing force and velocity
Violating the law of conservation of energy
 
ElmorshedyDr said:
the electron will only change direction with no velocity change

Just a very small point, but one which could cause you confusion… If the electron changes direction it's velocity is bound to change. That's because the velocity vector gives the direction of travel as well as the speed. [Velocity may be defined as the displacement (a vector) per unit time.] What you meant was that "the electron will only change direction with no speed change".
 
Philip Wood said:
Just a very small point, but one which could cause you confusion… If the electron changes direction it's velocity is bound to change. That's because the velocity vector gives the direction of travel as well as the speed. [Velocity may be defined as the displacement (a vector) per unit time.] What you meant was that "the electron will only change direction with no speed change".
I meant the magnitude of the velocity
 
I thought you probably did mean this, but using technical terms correctly is a good habit to get into.
 
It may be shown from the equations of electromagnetism, by James Clerk Maxwell in the 1860’s, that the speed of light in the vacuum of free space is related to electric permittivity (ϵ) and magnetic permeability (μ) by the equation: c=1/√( μ ϵ ) . This value is a constant for the vacuum of free space and is independent of the motion of the observer. It was this fact, in part, that led Albert Einstein to Special Relativity.
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