# What is permanent magnet B field equation?

• ShahinPhD
In summary, the conversation is about finding a formula to calculate the magnetic field strength (Tesla) between two permanent magnets with a distance of 10mm. The magnets are disk-shaped and have an intensity of 1.3T in their core and 0.6T on their surface. The formula provided involves using the charge density of the magnets and doubling it for two magnets. The person is looking for a simpler formula to use for their calculations.
ShahinPhD
I'm looking for an equation to calculate Tesla (B) between two permanent magnets with distance of 10mm.

Magnets are located in front of each other; disk shape and intensity of each is 1.3T in its core, and 0.6T on surface, so I'm interested how to calculate the B between them in distance of 5mm from each one (10mm between 2 magnets).

If the magnets are much longer than 5mm, the B field 5mm from the face of one magnet is the same as the E field 5mm from a uniformly charged disk with charge density
$$\sigma=M$$ where M=13,000 gauss (all in Gaussianl units). Just double it for two magnets.

It seems OK, but in a short form I'm looking for a formula to calculate the Tesla in distance between two magnets.
Suppose we have some parameters: dimensions of magnets, power of magnets in core and surface, distance between them; so how can we use a formula to calculate intensity between magnets in some distance?

(Frankly I'm looking for a formula to use for my calculations)

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The on axis formula for E due to a uniformly charged disk is in most (even elementary) textbooks.

## What is the formula for calculating the magnetic field of a permanent magnet?

The formula for calculating the magnetic field of a permanent magnet is B = μ₀(H + M), where B is the magnetic field, μ₀ is the permeability of free space, H is the external magnetic field, and M is the magnetization of the material.

## How do I determine the direction of the magnetic field of a permanent magnet?

The direction of the magnetic field of a permanent magnet is determined by the right-hand rule. If you point your thumb in the direction of the current, the direction of your fingers curling represents the direction of the magnetic field.

## What factors affect the strength of the magnetic field of a permanent magnet?

The strength of the magnetic field of a permanent magnet is affected by the material used, the size and shape of the magnet, and the external magnetic field it is exposed to. The strength can also be influenced by temperature and the orientation of the magnet.

## How does the magnetic field of a permanent magnet differ from an electromagnet?

The magnetic field of a permanent magnet is created by the alignment of the atoms in the material and does not require an external power source. An electromagnet, on the other hand, requires an electric current to produce a magnetic field.

## Can the magnetic field of a permanent magnet be changed?

The magnetic field of a permanent magnet is considered to be constant and cannot be changed. However, the strength of the magnetic field can be affected by external factors such as temperature and exposure to strong magnetic fields.

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