Does heating an electromagnet cause change in its magnetic field as well and vice versa?

amacorrit80
2022-07-20
Answered

Does heating an electromagnet cause change in its magnetic field as well and vice versa?

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Tolamaes04

Answered 2022-07-21
Author has **12** answers

your electromagnet is an inductor powered by a battery with constant potential $V$. The magnetic field is proportional to the intensity running on the wires. $B\propto I$. We know: $V=RI$, where $R$ is the resistance of the inductor. Its a very simple model as you can see...

For a small variation of temperature from initial temperature ${T}_{0}$, the resistance can be approximated with a linear relation:

$R=R({T}_{0})[1+\alpha (T-{T}_{0})]$

find $\alpha $ for a given material arround ${T}_{0}$ that you want to work with. So, in the vicinity of ${T}_{0}$, and with the temperature coeficient $\alpha $ measured/given, we can now conclude:

- If $\alpha >0$, resistance increases, current decreases, magnetic field decreases.

- If $\alpha <0$, resistance decreases, current increases, magnetic field increases.

- If $\alpha =0$, resistance decreases, current increases, magnetic field increases.

Temperature coeficient arround ${T}_{0}=293K$

For a small variation of temperature from initial temperature ${T}_{0}$, the resistance can be approximated with a linear relation:

$R=R({T}_{0})[1+\alpha (T-{T}_{0})]$

find $\alpha $ for a given material arround ${T}_{0}$ that you want to work with. So, in the vicinity of ${T}_{0}$, and with the temperature coeficient $\alpha $ measured/given, we can now conclude:

- If $\alpha >0$, resistance increases, current decreases, magnetic field decreases.

- If $\alpha <0$, resistance decreases, current increases, magnetic field increases.

- If $\alpha =0$, resistance decreases, current increases, magnetic field increases.

Temperature coeficient arround ${T}_{0}=293K$

asked 2022-05-20

How many neutral points can be obtained in a given plane perpendicular to the length of the two parallel wires conducting current in the same direction? Explain, Neglect earth's magnetic field of a bar magnet NS

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A bar magnet is held vertically above a horizontal metal ring, with the south pole of the magnet at the top. If the magnet is lifted straight up, will current run clockwise or counterclockwise in the ring, as seen from above?

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How can the integral form of Gauss's law for magnetism be described as a version of general Stokes' theorem? How does it follow?

asked 2022-07-23

What is the correct frame of reference for determining the magnetic force on a charge?

If two charges are both stationary in a given inertial frame, F1, then neither charge should experience a magnetic force due to the presence of the other charge (qv = 0). If we accelerate one charge, but not the other, then again, neither charge should experience a magnetic force, since only one charge has a non-zero velocity as measured in that inertial frame, meaning the other, stationary charge will experience no force in the magnetic field of the moving charge.

Now imagine that we are riding along as part of another inertial frame, F2, and that the first inertial frame discussed above that contains the two electrons F1, is traveling at a relative velocity of v from our perspective (i.e., it’s moving faster than us). Now imagine that we fire two electrons from our inertial frame F2, towards F1, one that travels at a velocity of v from our perspective, thereby traveling at the same velocity as the electron that appeared stationary in F1, and another that travels at the same velocity as the second, "faster" electron.

From our perspective in F2, both electrons have a non-zero velocity: the “slow one” traveling at a velocity of v, and the “fast one” traveling a bit faster than that. From our perspective, in F2, both electrons should experience a magnetic force of attraction due to their non-zero velocities in non-zero magnetic fields, which would change the path of those electrons from the perspective of both inertial frames.

However, from the perspective of F1, the “slow” electron is stationary, and should not experience any magnetic force in any magnetic field.

This seems to not make sense - what would happen as an experimental matter?

If two charges are both stationary in a given inertial frame, F1, then neither charge should experience a magnetic force due to the presence of the other charge (qv = 0). If we accelerate one charge, but not the other, then again, neither charge should experience a magnetic force, since only one charge has a non-zero velocity as measured in that inertial frame, meaning the other, stationary charge will experience no force in the magnetic field of the moving charge.

Now imagine that we are riding along as part of another inertial frame, F2, and that the first inertial frame discussed above that contains the two electrons F1, is traveling at a relative velocity of v from our perspective (i.e., it’s moving faster than us). Now imagine that we fire two electrons from our inertial frame F2, towards F1, one that travels at a velocity of v from our perspective, thereby traveling at the same velocity as the electron that appeared stationary in F1, and another that travels at the same velocity as the second, "faster" electron.

From our perspective in F2, both electrons have a non-zero velocity: the “slow one” traveling at a velocity of v, and the “fast one” traveling a bit faster than that. From our perspective, in F2, both electrons should experience a magnetic force of attraction due to their non-zero velocities in non-zero magnetic fields, which would change the path of those electrons from the perspective of both inertial frames.

However, from the perspective of F1, the “slow” electron is stationary, and should not experience any magnetic force in any magnetic field.

This seems to not make sense - what would happen as an experimental matter?

asked 2022-05-09

What I understand is that Synthetic magnetism is just a fancy name of a method to make a charge neutral particle act like it is in a magnetic field.

A charged particle in a magnetic field acquires a geometric phase, so a neutral particle if by any method is able to acquire this geometric phase, then that method is said to create a synthetic magnetic field.

A charged particle in a magnetic field acquires a geometric phase, so a neutral particle if by any method is able to acquire this geometric phase, then that method is said to create a synthetic magnetic field.

asked 2022-05-19

I know that there is some relationship between electric current and magnetism, but I am having trouble pinning down the exact relationship. Is electric current a necessary condition for the existence of magnetic field? And is electric current a sufficient condition for the existence of magnetic field?

In other words, is it true that "there is electric current if and only if there is a magnetic field"?

In other words, is it true that "there is electric current if and only if there is a magnetic field"?

asked 2022-04-30

Does protons moving parallel to each other exert magnetic force?

If two protons are moving parallel to each other in same direction with equal velocities then do they exert magnetic force on each other.? As protons are moving they should produce magnetic field and there should be some magnetic force + electric force on each of them. But if look from their refrence frame then both the protons are at rest and hence there will be no magnetic force (as magnetic field is created by a moving charge), only electric force on each of them. How can this be possible that force(magnetic force) on a particle becomes different on changing the reference frame even though the reference frames are non accelerating with respect to each other?

If two protons are moving parallel to each other in same direction with equal velocities then do they exert magnetic force on each other.? As protons are moving they should produce magnetic field and there should be some magnetic force + electric force on each of them. But if look from their refrence frame then both the protons are at rest and hence there will be no magnetic force (as magnetic field is created by a moving charge), only electric force on each of them. How can this be possible that force(magnetic force) on a particle becomes different on changing the reference frame even though the reference frames are non accelerating with respect to each other?