# Magnetic Flux Density | Definition and Formula

Want create site? Find Free WordPress Themes and plugins.

## Magnetic Flux Density

Flux density is the measure of the number of magnetic lines of force per unit of cross-sectional area.

While the total amount of the flux produced by a magnet is important, we are more interested in how dense or concentrated, the flux is per unit of cross-sectional area. Flux per unit of cross-sectional area is called flux density.

Magnetic Flux Density Formula

Its letter symbol is B. The relationship between total flux and flux density is given by the following equation:

$B=\frac{\varphi }{A}$

Where

B=flux density in Tesla

φ=total magnetic flux in weber

A= Cross-sectional area in square meter

Magnetic Flux Density Unit

The SI Unit for flux density is the Tesla (T) which is defined as;

$B=\frac{\varphi }{A}$

$B=\frac{Wb}{{{m}^{2}}}=Tesla$

“If one line of magnetic field passes normally through m2 area, the magnetic flux density, B, will be one Tesla,

## Example of Magnetic Flux Density

Calculate the flux density in a ferromagnetic material with a cross-sectional area of 0.01 m2 containing 100 lines.

Solution

We know that 100 lines equal to 1 μWb. By using following formula, we can calculate the flux density B

$B=\frac{\varphi }{A}$

$B=\frac{1~\mu ~Wb}{1*{{10}^{-2}}{{m}^{2}}}=\frac{1*{{10}^{-6}}~Wb}{1*{{10}^{-2}}{{m}^{2}}}=1*~{{10}^{-4}}~T$

## Example of Magnetic Flux Density

Determine the cross- sectional area of a toroid that has a flux of 0.5 Wb and a flux density of 25 T.

Solution

We have the following formula to calculate cross-sectional area:

$A=\frac{\varphi }{B}=\frac{0.5~Wb}{25~{}^{Wb}/{}_{{{m}^{2}}}}=2*~{{10}^{-2~}}{{m}^{2}}$

## Example of Magnetic Flux Density

An air core coil has 0.65 μ Wb of flux in its core. Calculate the flux density if the core diameter is 4 cm.

Solution

First calculate the area of the core:

$A=\pi ~{{r}^{2}}=3.14*{{\left( 0.02m \right)}^{2}}=1.256*~{{10}^{-3}}~{{m}^{2}}$

Now, calculate the flux density using following formula:

$B=\frac{\varphi }{A}=~\frac{0.65*~{{10}^{-6}}~Wb}{1.256*~{{10}^{-3}}~{{m}^{2}}}=5.175*~{{10}^{-4}}~T$

Magnetomotive Force and Unit

Magnetic Flux Definition and Unit

Magnetic Flux Intensity Definition and Unit

Did you find apk for android? You can find new Free Android Games and apps.

### 3 thoughts on “Magnetic Flux Density | Definition and Formula”

1. I’m amazed, I have to admit. Rarely do I encounter a blog
that’s both equally educative and amusing, and let me
tell you, you have hit the nail on the head.
The issue is something which not enough men and women are
speaking intelligently about. I am very happy that I came across
this during my hunt for something concerning this.

• Thank you…