All Questions
22 questions
1
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2
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81
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Is Coulomb written/found on any object/product as its unit?
Today I had physics class and the unit Coulomb made me wonder as to why it was even invented when I don't see it being used anywhere. When I asked where it may be shown just like bulbs have x Watts ...
- 21
0
votes
2
answers
222
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Why isn't the charge of an electron taken to be "$-1.6 \times 10^{-19}$ coulombs" [closed]
Even though we refer to electrons being negatively charged, why is it that we don't write the charge as "-1.6 × 10^-19 coulombs"?
- 49
-2
votes
2
answers
130
views
Why can the Ampere not be defined as the flow of $n$ Coulomb in $n$ seconds?
1 Ampere is defined as the flow of 1 Coulomb of charge in one second. However, I do not understand why it cannot be defined as the flow of n Coulomb of charge in n seconds.
This definition is ...
7
votes
1
answer
500
views
Illogical choice for the new definition of the charge of the electron by the 28th General Conference on Weights and Measures
The present definition of the Coulomb, since May 20th 2019, is that one electron has a charge of exactly
$1.602176634 \times 10^{-19} $C
Previously, the Coulomb was defined (through the Lorentz force ...
- 4,448
2
votes
1
answer
338
views
Why are Amperes and moles both base units?
Current and "amount of substance" are base units
The SI system treats both electric current and "amount of substance" as a quantity that is measured in "fundamental" or &...
- 345
52
votes
6
answers
7k
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Has anyone charged an object with 1 coulomb? Why was such a ridiculously large charge chosen as the unit of charge?
The fact that two balls charged with 1 coulomb each would repel/attract each other from a distance of 1 metre with a force sufficient to lift the Seawise Giant would suggest me otherwise, but has ...
- 1,127
1
vote
0
answers
163
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What happened to the Planck charge on Wikipedia? [closed]
Wikipedia used to have a nice article about the Planck units, with contributions made directly by Don Page.
I recently visited the current article and the Planck charge kind of disappeared. I also saw ...
- 1,127
3
votes
1
answer
687
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Scientific Notation for Different Units of Charge
Sorry in advance for the basic question, I’m pretty new to physics. I’m doing some electromagnetism homework and so far in class we’ve used only nano and micro coulombs in our force and electric field ...
- 33
0
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1
answer
739
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What do we exactly mean by charge and why the elementary charge of electron is $1.602176634×10^{−19} C$? [closed]
A coulomb is 6.241 x 10^18 elementary charges. But what exactly is a coulomb? And what do we mean exactly by a charge? how was it measured?
- 21
17
votes
3
answers
5k
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Why is ampere still a base unit? [duplicate]
The ampere is still a base unit, according to the SI brochure. However, in my perception the recent redefinition of units effectively defines the Coulomb as e/(1.602 176 634 × 10^−19), and the ampere ...
- 2,629
0
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1
answer
66
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Electrostatics, measurement of charge
How did physicists come up with a standard for measuring charge? How an electrical measurement of charge was made?
- 1
2
votes
1
answer
622
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Why is a Coulomb the charge of $6.24 \times 10^{18}$ electrons? [duplicate]
Where does the $6.24 \times 10^{18}$ number come from? How was it historically derived?
I know that $1$ C $=$ $1$ A s but that just pushes the question down another step, and another and another, at ...
- 123
2
votes
1
answer
277
views
Why does one Coulomb equal that strange number? [duplicate]
Why is one Coulomb equal to 6.24 *10^18 ?
This number is weird . why wasn't it a nice number like 10^20.
I have some guesses about this.
- 331
3
votes
3
answers
1k
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Why are there $1 / 1.602176634 \times 10^{-19}$ electrons in a coulomb?
Why that exact number of electrons in one coulomb? who decided it? there is nothing wrong with the number, it just seems slightly messy. Why didn't the scientific community just settle on an easier ...
2
votes
2
answers
829
views
Is there (or was there) a unit of electric current based on Avogadros number or Coulombs constant?
This has to do with the SI definition of the Ampere. Why the quantity $2*10^{-7} $ Newtons in particular? It would make more sense to define 1 Ampere = 1 mole of electron charge per second. Which ...
- 439
1
vote
1
answer
566
views
How did Coulomb arrive at value of electron charge?
Charge of one electron is known to be as $1.6$ x $10^{-19}$ C or alternative 1 Coulomb contains charge of $6.24$ x $10^{18}$ electrons. I am just wondering if these numbers are arbitrarily chosen or ...
- 113
1
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2
answers
8k
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What actually is 1 coulomb? Is it number of electrons or the amount of force?
I've just started my highschool, only to land in the beautiful world of electricity and magnetism, I have many queries and dilemmas, so I want some guidance. Now on to the question.
I've just read ...
- 19
0
votes
1
answer
3k
views
Why is a Coulomb not a fundamental unit? [duplicate]
Why is a coulomb not a fundamental unit but an ampere is considering that a coulomb is more ' fundamental '?
- 295
6
votes
4
answers
2k
views
Why are electrical units (specifically, electrical current) considered a base unit?
Note: this is NOT a question why current is the base unit as opposed to charge—that’s because measuring $1 \ \mathrm{ A }$ through a wire is easier to measure in a lab than is $1 \ \mathrm{ C }$ in ...
2
votes
1
answer
160
views
Absence of "charge" as a fundamental unit in natural system
In natural system of units, using speed of light, Planck's constant, and eV (for energy), we express "charge" dimension as:
$[charge]=[Force]^{1/2}[length] $ (from Coloumb's law equation)
There is ...
user122637
4
votes
1
answer
11k
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Why is charge not taken as a fundamental unit? [duplicate]
According to the definition of electric current, it appears to be a derived quantity. Charge on the other hand seems more fundamental than electric current. Then why is current taken as fundamental ...
- 1,804
67
votes
2
answers
32k
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Why is the ampere a base unit and not the coulomb?
I always thought of current as the time derivative of charge, $\frac{dq}{dt}$. However, I found out recently that it is the ampere that is the base unit and not the coulomb. Why is this? It seems to ...
- 1,760