# Question of units of B, H in Gaussian system

1. Nov 23, 2011

### Master J

In "Classical Theory of Fields", by Landau & Lifgarbagez, they give, for example, the force on a charged particle by a magnetic field as:

F = $\frac{ev}{c}$ x H

where H is the magnetic field intensity. Now, normally written in SI units, this expression would use B and no factor of 1/c.

So how are B and H related here? I'm a bit confused over the units in use (which I think may be Gaussian)!

2. Nov 24, 2011

### Meir Achuz

In Gaussian units, B and H have the same units (gauss), and are identical in free space.
For sonme historical reason (and a bit of confusion) H was originally given the unit 'Oersted' with 1 Oersted = 1 Gauss.

3. Nov 24, 2011

### Meir Achuz

In Gaussian units, B and H have the same units (gauss), and are identical in free space.
For some historical reason (and a bit of confusion) H was originally given the unit 'Oersted' with 1 Oersted = 1 Gauss.

4. Nov 24, 2011

### Master J

So in Gaussian units, B and H are entirely interchangeable?

5. Nov 25, 2011

### Bill_K

In Gaussian units, B and H have the same units (gauss), and are identical in free space.