Vacuum permittivty with alternative Standard-Unit for meters

The important thing is that the values of all the defining constants (e, c, ##\hbar##, etc.) are kept consistent with each other and with the new definition of the meter.
  • #1
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Value of Permettivity when 1m would be 1,10m
I was wondering: what would be the value of Vacuum Permettivity in the case 1 meter (say 1m") would be defined as the distance we nowadays see as 1,10 meters.

At first this looks easy: ##\varepsilon0 = 8.8541878128 \cdot 10{^{12}}## F / m with normal meters
so ##\varepsilon0" = \varepsilon0 \cdot 1.1##
##\varepsilon0" = 9.739660659408 \cdot 10{^{12}}## F / m" with converted meters.

However, when I look at Farads, this is defined as $$\frac{s^4 \cdot A^2}{m^2 \cdot kg}$$ so Farads should be converted too.

And Amperes are defined as:
"The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed one metre apart in vacuum, would produce between these conductors a force equal to ##2 \cdot 10^{−7}## Newtons per metre of length."

which also involves meters, and Newtons, which are defined as $$\frac{kg \cdot m}{s^2}$$

this all makes it too tough for me.

So, in short, my question is: is the calculated version of E0" correct?
 
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GoodQuestion said:
And Amperes are defined as:
"The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed one metre apart in vacuum, would produce between these conductors a force equal to 2⋅10−7 Newtons per metre of length."
That is the old definition. The modern definition is: "The ampere, symbol A, is the SI unit of electric current. It is defined by taking the fixed numerical value of the elementary charge e to be ##1.602176634×10^{−19}## when expressed in the unit C, which is equal to A s, where the second is defined in terms of ##∆ν_{Cs}##."

see: https://www.bipm.org/utils/common/pdf/si-brochure/SI-Brochure-9-EN.pdf

GoodQuestion said:
I was wondering: what would be the value of Vacuum Permettivity in the case 1 meter (say 1m") would be defined as the distance we nowadays see as 1,10 meters.
Under the current definitions of the SI the meter is defined as: "The metre, symbol m, is the SI unit of length. It is defined by taking the fixed numerical value of the speed of light in vacuum c to be 299792458 when expressed in the unit m/s, where the second is defined in terms of ##∆ν_{Cs}##."

So, if 1 METRE = 1.1 metre then c = 299792458 metre/second = 272538598 METRE/second

Then, since in the current SI we have $$\epsilon_0=\frac{e^2}{4 \pi \alpha \hbar c}$$ Thus, keeping all other SI defining constants the same and keeping physics the same, we simply have a reduction in the numerical value of c by a factor of 1.1 and thus an increase in the numerical value of ##\epsilon_0## by a factor of 1.1

GoodQuestion said:
So, in short, my question is: is the calculated version of E0" correct?
Yes, but you shouldn't write it in units of F/m since you have changed the units.
 
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  • #3
Shouldn't ##\hbar## change also, because there's a meter in there as well?

Assuming the value of KG en second stays the same, shouldn't this lead to ##\varepsilon0##" becomes ##\varepsilon0 \cdot 1,1{^3}## ?
 
  • #4
GoodQuestion said:
Shouldn't ##\hbar## change also, because there's a meter in there as well?
It is not necessary, but you certainly could do that if you wish.
 

FAQ: Vacuum permittivty with alternative Standard-Unit for meters

What is vacuum permittivity?

Vacuum permittivity, also known as electric constant, is a physical constant that represents the ability of vacuum to permit the flow of electric charge.

What is the alternative standard unit for meters in vacuum permittivity?

The alternative standard unit for meters in vacuum permittivity is the Coulomb squared per newton square meter (C^2/Nm^2).

Why is there an alternative standard unit for meters in vacuum permittivity?

The alternative standard unit for meters in vacuum permittivity is used to simplify equations and calculations in electromagnetism, as it eliminates the need for the constant 1/4πε0.

How is vacuum permittivity measured?

Vacuum permittivity is measured experimentally using various techniques such as capacitance measurements and Coulomb's law.

What is the value of vacuum permittivity in the alternative standard unit for meters?

The value of vacuum permittivity in the alternative standard unit for meters (C^2/Nm^2) is approximately 8.854 x 10^-12.

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