Question of units of B, H in Gaussian system

In summary, the force on a charged particle by a magnetic field can be expressed as F = \frac{ev}{c} x H in the Classical Theory of Fields by Landau & Lifgarbagez. This expression uses H as the magnetic field intensity, which is equivalent to B in Gaussian units. In Gaussian units, B and H have the same units (gauss), and are identical in free space. However, for historical reasons, H was originally given the unit 'Oersted' with 1 Oersted = 1 Gauss, causing some confusion.
  • #1
Master J
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In "Classical Theory of Fields", by Landau & Lifgarbagez, they give, for example, the force on a charged particle by a magnetic field as:

F = [itex]\frac{ev}{c}[/itex] 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)!
 
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  • #2
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
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
So in Gaussian units, B and H are entirely interchangeable?
 
  • #5
In Gaussian units, B and H have the same units (gauss), and are identical in free space.
 

1. What is the Gaussian system of units?

The Gaussian system of units is a system of measurement commonly used in physics and engineering. It is based on the centimeter-gram-second (CGS) system of units, and its defining feature is the use of the centimeter, gram, and second as base units.

2. What are the units of B and H in the Gaussian system?

The unit of magnetic flux density, B, in the Gaussian system is the gauss (G), and the unit of magnetic field intensity, H, is the oersted (Oe). These units are related to the SI units of tesla (T) and ampere per meter (A/m) by the following conversions: 1 G = 10-4 T and 1 Oe = 103 A/m.

3. How are B and H related in the Gaussian system?

In the Gaussian system, B and H are related by the permeability of free space, μ0, which is defined as 4π × 10-7 H/m. This relationship is expressed as B = μ0H.

4. Why is the Gaussian system still used?

The Gaussian system is still used in some fields, such as electromagnetism, because it has certain advantages over the SI system. For example, calculations involving electromagnetic quantities are often simpler in the Gaussian system due to the use of natural units, where the speed of light, c, is equal to 1. It is also sometimes used for historical reasons or for consistency with older literature.

5. What are the drawbacks of the Gaussian system?

One drawback of the Gaussian system is that it is not a coherent system, meaning that derived units are not related by powers of ten. This can make conversions between different units more complicated. Additionally, the use of natural units can be confusing for those not familiar with the system. The Gaussian system is also not as widely used as the SI system, which can make communication and collaboration with others more challenging.

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