Units of measure for Electric and Magnetic Fields

[atomicpedals]

I'm going in circles on units (or perhaps more accurately different unit systems). The two my professor has chosen to work in are Gaussian units and MKSA units. My problem is one of lack of understanding; are the units of measure for electric and magnetic fields in these systems:

Gaussian: E = n/C; B = n-s/C-m
MKSA: E = n/C; B = w/m^2

Thanks!

 

[Andrew Mason]

I'm going in circles on units (or perhaps more accurately different unit systems). The two my professor has chosen to work in are Gaussian units and MKSA units. My problem is one of lack of understanding; are the units of measure for electric and magnetic fields in these systems:

Gaussian: E = n/C; B = n-s/C-m
MKSA: E = n/C; B = w/m^2

Gaussian units use the statCoulomb for charge which is defined in such a way as to remove the proportionality constant from Coulomb's law:

$$F = qQ/r^2$$

So charge in statCoulombs has dimensions of force^1/2 x distance or grams^1/2cm^3/2/sec.

E in MKS has dimensions of force/charge (Newtons/Coulomb) or potential/distance (Volts/Metre or Joules/Coulomb-metre) and in Gaussian units it has units of dynes/statCoulomb or statV/cm

You will soon realize that Gaussian units in Electricity and Magnetism were invented by purists who hated students.

In MKS B has dimensions of force-time/charge-distance ie: F = q(E + v x B). So the magnetic field has units of Newtons-sec/Coulomb-metre or Teslas. But in Gaussian units, B has dimensions of force/charge just like E, so its units are dynes/statC or Gauss. 1 Gauss = .0001 Tesla x 1 m/sec.

AM

 

[atomicpedals]

Thanks! Hopefully I'll keep them straight too!

"You will soon realize that Gaussian units in Electricity and Magnetism were invented by purists who hated students."

It's what I get for taking classes taught by theorists.