Formula for Magnetic field at a distance

[Muhammad Umair Khan]

How can i mathematically calculate (or represent) a magnetic field at any certain distance from a magnet or a solenoid?

 

[(*steve*)]

Once you are far enough away, the intensity falls with the square of the distance.

This doesn't work when you're really close.

 

[Muhammad Umair Khan]

Once you are far enough away, the intensity falls with the square of the distance.

This doesn't work when you're really close.

What about a distance of 3 to 10 cm??? and how does the relation change with it?

 

[(*steve*)]

What about a distance of 3 to 10 cm??? and how does the relation change with it?

It depends. If the magnet (or solenoid) is only a couple of mm in size, then yes. If it's a 20cm cube, then no.

 

[BobK]

Once you are far enough away, the intensity falls with the square of the distance.

Unless you have found a magnetic monopole, it falls off as the cube of the distance (field of a dipole.)

Near one pole, or near a long straight piece of wire carrying a current, it would be inverse square.

Bob

 

[Muhammad Umair Khan]

Unless you have found a magnetic monopole, it falls off as the cube of the distance (field of a dipole.)

Near one pole, or near a long straight piece of wire carrying a current, it would be inverse square.

Bob

Thanks Bob, but could you put it in a mathematical equation please?

 

[BobK]

Look up dipole field on google.

Bob