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Magnetic Flux= BA is A the surrounding area affected by the flux or the area of the coil itself that is affected by the flux
ElmorshedyDr said:Magnetic Flux= BA is A the surrounding area affected by the flux or the area of the coil itself that is affected by the flux
ElmorshedyDr said:I mean if a I straight wire with no current is placed in a magnetic field, how can I calculate the Flux affecting the wire using flux=BA
Thanks a lot but I can't understand these equationsphy_infinite said:In any calculation with the flux being [tex] \Phi \equiv \int \mathbf{B} \cdot d \mathbf{a} [/tex] it's always best to integrate over the area of the loop of wire.
If you have a straight wire, there is no flux to calculate. If there is no current, or if the wire is not moving in the magnetic field, then the magnetic field has no effect on the electrons in the wire because of the Lorentz force law: [tex] \mathbf{F}_{mag} = Q(\mathbf{v} \times \mathbf{B}) [/tex]
phy_infinite said:In any calculation with the flux being [tex] \Phi \equiv \int \mathbf{B} \cdot d \mathbf{a} [/tex] it's always best to integrate over the area of the loop of wire.
If you have a straight wire, there is no flux to calculate. If there is no current, or if the wire is not moving in the magnetic field, then the magnetic field has no effect on the electrons in the wire because of the Lorentz force law: [tex] \mathbf{F}_{mag} = Q(\mathbf{v} \times \mathbf{B}) [/tex]
What I want to know is If I have a straight wire placed perpendicularly to a magnetic field, how can I calculate the flux affecting the wire " the wire is still, there is no motion"rude man said:If you have a round, single-turn coil with a smll gap in it somewhere, and a time-varying B field is present in-line with the coil's normal vector, then there is also no motion nor current, yet there is an emf developed across the gap. So this argument is questionable.
Not that I know the answer. If I have a rectangular path in air but with the wire forming one of the four sides, there is similarly emf developed around that path with the same time-varying B field. The question is, what portion of the emf is along the wire?
rude man said:If you have a round, single-turn coil with a smll gap in it somewhere, and a time-varying B field is present in-line with the coil's normal vector, then there is also no motion nor current, yet there is an emf developed across the gap. So this argument is questionable.
Not that I know the answer. If I have a rectangular path in air but with the wire forming one of the four sides, there is similarly emf developed around that path with the same time-varying B field. The question is, what portion of the emf is along the wire?
The equation [tex]\Phi \equiv \int \mathbf{B} \cdot d \mathbf{a}[/tex] is simply a more specific definition than the one you gave; [itex] \Phi = B \cdot A [/itex] which is really just a special case. The equation [tex]\mathbf{F}_{mag} = Q(\mathbf{v} \times \mathbf{B})[/tex] is saying that the magnetic force on a charge Q is proportional to the strength of the magnetic field and the velocity of the charge. If a wire isn't moving or there is no current, then there is no magnetic force.ElmorshedyDr said:Thanks a lot but I can't understand these equations
ElmorshedyDr said:What I want to know is If I have a straight wire placed perpendicularly to a magnetic field, how can I calculate the flux affecting the wire " the wire is still, there is no motion"
I mention that point, because I couldn't understand how does magnetic flux changes when moving the wire where it cuts the field lines as the wire covers a certain area, it seams non logical to calculate the flux using the area covered by wire !phy_infinite said:If the wire is not in a loop but open straight, I don't see the point in calculating the flux. I honestly haven't come across this problem, but I assume it's because you aren't going to get any current out of it, at least not for long.
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ElmorshedyDr said:I mention that point, because I couldn't understand how does magnetic flux changes when moving the wire where it cuts the field lines as the wire covers a certain area, it seams non logical to calculate the flux using the area covered by wire !
Isn't the change calculated from : Delta area x flux density / delta time ?phy_infinite said:The magnetic flux may not change when moving any wire. By moving the wire, you are setting the charges in motion with respect to the magnetic field, so even if the magnetic field is not changing, the magnetic force is acting on the charges.
ElmorshedyDr said:Isn't the change calculated from : Delta area x flux density / delta time ?
Then when do I use the equation Blvphy_infinite said:If the magnetic field is constant, then as you move the wire, the flux is constant and does not change.
ElmorshedyDr said:Then when do I use the equation Blv
ElmorshedyDr said:Isn't the change calculated from : Delta area x flux density / delta time ?
I said earlier the wire is moving there is a vrude man said:Whenever there is a B, an l and a v. In your case there is no v. So the emf = 0 irrespective of the time behavior of B.
I can't understand how changing area changes flux since the geometrical shape of wire is constant so the flux should be constant!phy_infinite said:Also if the magnetic field doesn't change, a changing area also changes the flux.
phy_infinite said:If the magnetic field is constant, then as you move the wire, the flux is constant and does not change.
ElmorshedyDr said:I can't understand how changing area changes flux since the geometrical shape of wire is constant so the flux should be constant!
ElmorshedyDr said:I can't understand how changing area changes flux since the geometrical shape of wire is constant so the flux should be constant!
ElmorshedyDr said:I can't understand how changing area changes flux since the geometrical shape of wire is constant so the flux should be constant!
Magnetic flux is a measurement of the total magnetic field passing through a given area. It is represented by the symbol Φ and is measured in units of webers (Wb).
Magnetic flux is calculated by multiplying the magnetic field strength (B) by the area (A) perpendicular to the field. The formula for magnetic flux is Φ = B x A.
Coil wire refers to a length of thin, insulated wire that has been wound into a coil shape. It is commonly used in the construction of electromagnets and inductors.
The presence of a coil wire can increase or decrease the magnetic flux depending on the direction of the current flowing through it. When current flows in the same direction as the magnetic field, the flux increases. When current flows in the opposite direction, the flux decreases.
Magnetic flux and coil wire are used in a variety of applications, including generators, motors, transformers, and MRI machines. They also play a crucial role in electrical power transmission and distribution systems.