- #1
chanderjeet
- 25
- 0
i'm having trouble distinguishing between magnetic flux and magnetic flux density...can someone please explain to me?
also why is it sometimes used interchangeably?
also why is it sometimes used interchangeably?
Magnetic flux density vs magnetic flux
- Thread starter chanderjeet
- Start date
In summary, magnetic flux density is a vector, measured in webers per square metre (or teslas), and exists at each point. Magnetic flux is measured in volt-seconds, and magnetic flux density is what physicists more commonly call the magnetic field.
- #2
tiny-tim
Science Advisor
Homework Helper
- 25,839
- 258
Hi chanderjeet! 
Magnetic flux, Φ, is a scalar, measured in webers (or volt-seconds), and is a total amount measured across a surface (ie, you don't have flux at a point).
Magnetic flux density, B, is a vector, measured in webers per square metre (or teslas), and exists at each point.
The flux across a surface S is the integral of the magnetic flux density over that surface:
Magnetic flux density is what physicists more commonly call the magnetic field.
It is a density per area, rather than the usual density per volume.
(and they can't be used interchangeably)
Magnetic flux, Φ, is a scalar, measured in webers (or volt-seconds), and is a total amount measured across a surface (ie, you don't have flux at a point).
Magnetic flux density, B, is a vector, measured in webers per square metre (or teslas), and exists at each point.
The flux across a surface S is the integral of the magnetic flux density over that surface:
Φ = ∫∫S B.dS
(and is zero for a closed surface)Magnetic flux density is what physicists more commonly call the magnetic field.
It is a density per area, rather than the usual density per volume.
(and they can't be used interchangeably)
Similarly, electric flux is a scalar, measured in volt-metres, and electric flux density (also a density per area), E, is a vector, measured in volts per metre (and is more commonly called the electric field).
- #3
chanderjeet
- 25
- 0
that really cleared things up...thank you.
- #4
Bob S
- 4,662
- 7
There is also H, magnetization, measured in amp-turns per meter (in MKS units).
Bob S
Bob S
- #5
MikeHansen
- 3
- 0
Some sources say that magnetic flux density is not related to current but to VOLTAGE. I don't understand why. I always thought that the magnetic field in a wire is caused by the movement of charged elements (e.g electrons) in a wire. Can you explain this?
- #6
MikeHansen
- 3
- 0
In some litterature this formula is used:
Bmax = Vmax/ (2*pi*f * A * n)
Where Bmax is the max magnetic flux density, Vmax is the max voltage over a coil with n turns wound on a toroid core with area A. 2*pi*f is the rate of voltage change per time unit.
It looks like the magnetic flux density is reduced :
If we increase the number of turns. Why?
If we increase the area. Why?
If we increase the rate of change of voltage applied. Why?
It looks like the magnetic flux density is increased:
If the max VOLTAGE is increased. Why? Isnt it the current that causes the flux density to increase?
I would appreciate a thorough and intuitive explanation!
Mike Hansen
Bmax = Vmax/ (2*pi*f * A * n)
Where Bmax is the max magnetic flux density, Vmax is the max voltage over a coil with n turns wound on a toroid core with area A. 2*pi*f is the rate of voltage change per time unit.
It looks like the magnetic flux density is reduced :
If we increase the number of turns. Why?
If we increase the area. Why?
If we increase the rate of change of voltage applied. Why?
It looks like the magnetic flux density is increased:
If the max VOLTAGE is increased. Why? Isnt it the current that causes the flux density to increase?
I would appreciate a thorough and intuitive explanation!
Mike Hansen
1. What is the difference between magnetic flux density and magnetic flux?
Magnetic flux density, also known as magnetic field strength, is a measure of the strength of a magnetic field at a given point. It is represented by the symbol B and is measured in units of tesla (T). On the other hand, magnetic flux is a measure of the total amount of magnetic field passing through a given area. It is represented by the symbol Φ and is measured in units of weber (Wb).
2. How are magnetic flux density and magnetic flux related?
Magnetic flux density and magnetic flux are related by the equation B = Φ/A, where A is the area through which the magnetic field is passing. This means that the magnetic flux density is directly proportional to the magnetic flux and inversely proportional to the area.
3. What factors affect the magnetic flux density?
The magnetic flux density at a given point is affected by the strength of the magnetic field, the distance from the source of the field, and the angle at which the field lines intersect the surface. Additionally, the permeability of the material through which the field is passing can also affect the magnetic flux density.
4. How is magnetic flux density measured?
Magnetic flux density can be measured using a device called a magnetometer, which detects and measures the strength of the magnetic field. The unit of measurement for magnetic flux density, tesla, was named after the inventor and physicist Nikola Tesla.
5. Why is understanding magnetic flux density important in science?
Understanding magnetic flux density is important in science because it helps us to understand the behavior of magnetic fields and their effects on various materials and objects. It is also essential in the design and operation of many devices, such as motors, generators, and electronic circuits, which rely on magnetic fields for their functioning.
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