Why am I getting two different results in emu and SI unit?

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faheemahmed6000
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I am computing force between two magnetic poles each of one unit pole (in emu) and situated one centimeter apart.

In electromagnetic units:
##F_{dyne}=\dfrac{p^2}{r_{cm}^2}=\dfrac{1^2}{1^2}=1 dyne##
where ##p## is pole strength in emu

In SI units:
##F_{N}=k_A \dfrac{P^2}{r_m^2}=10^{-7} \dfrac{({1.25\times 10^{-7}})^2}{10^{-4}}=1.5625 \times 10^{-17} \neq 10^{-5}N=1dyne##
where ##P## is that same pole strength in SI units

with ##P=1.25\times10^{-7}p## (see here)

Now why am I getting two different results in emu and SI for the same configuration?
 
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The units in the formula "in SI units" don't match, at least not if ka is supposed to be ##\frac{\mu_0}{4 \pi}## as the numerical value used for it would suggest.
Working with units helps to spot errors.
 
mfb said:
The units in the formula "in SI units" don't match, at least not if ka is supposed to be ##\frac{\mu_0}{4 \pi}## as the numerical value used for it would suggest.
Working with units helps to spot errors.
Please can you explain a bit more elaborately?
 
faheemahmed6000 said:
In electromagnetic units:
##F_{dyne}=\dfrac{p^2}{r_{cm}^2}=\dfrac{1^2}{1^2}=1 dyne##
where ##p## is pole strength in emu
I agree with @mfb. You need to show the units in each of your intermediate steps. As it is, I can tell that F is in dyne and r is in cm, but I cannot tell if p is in abC or statC. If it is abC then your equation is wrong, and if it is in statC then you are using electrostatic units not electromagnetic units.