Coulomb's Law Question
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The force is in newtons. There isn't enough information given to determine the two charges. The force is proportional to the product of the two charges divided by the distance squared. So you would at least need to know the ratio between the two charges.
See
http://en.wikipedia.org/wiki/Coulomb's_law
http://www.physicsclassroom.com/class/estatics/u8l3b.cfm
See
http://en.wikipedia.org/wiki/Coulomb's_law
http://www.physicsclassroom.com/class/estatics/u8l3b.cfm
Charges and Potenial difference confusing
Charges and Potenial difference confusing
This has been confusing me. We have negative (charges) electrons flowing because there is a difference of potenial in the Dc power source. The charges flow to the positive side of the DC source. They then flow from the positve side in the DC source to the negative side in the DC source. The negative side of the DC source continues to have a excess of negative (charges) electrons. I would think that positive charges would be needed to attach the negative charges. I don't know what to call the positive charges?
Charges and Potenial difference confusing
This has been confusing me. We have negative (charges) electrons flowing because there is a difference of potenial in the Dc power source. The charges flow to the positive side of the DC source. They then flow from the positve side in the DC source to the negative side in the DC source. The negative side of the DC source continues to have a excess of negative (charges) electrons. I would think that positive charges would be needed to attach the negative charges. I don't know what to call the positive charges?
Free electrons are produced by a chemical reaction at the negative terminal. They are absorbed at the positive terminal, causing another chemical reaction. See
http://library.kcc.hawaii.edu/external/chemistry/everyday_electro.html
http://library.kcc.hawaii.edu/external/chemistry/everyday_electro.html
- Location
- Lockport, IL
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- Retired Electrical Engineer
Some have used the phrase, "holes in the atoms where electrons are supposed to reside," or simply "holes." If an atom that is "missing and electron" (i.e., is a positively charged "hole") obtains an electron from its neighbor to the left, you can say that a negative charge moved to the right, or that a positive "hole" moved to the left. They are functionally identical. By convention, current is described in terms of the motion of positive charges, despite the fact (perhaps not known when the convention was first adopted) that it is a negatively charged particle that is actually in motion.
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Correct (almost). The motion of protons is seldom the physical basis for current flow. But as to Avogado, his number of 6.023 E23 would be the number of electrons that you would have, if you had a "mole" of electrons.
LarryFine
Master Electrician Electric Contractor Richmond VA
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- Henrico County, VA
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- Electrical Contractor
You guys are such nerds! :roll: ()
)
mikeames
Senior Member
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- Germantown MD
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- Teacher - Master Electrician - 2017 NEC
I was going to mention this but then I figured....... Someone will think I googled it. I memorized it a while back along with many others formulas capacitive (1 over 2 pi fc squared) and inductive reactance ( 2 pi fl) simply to learn it. I may be wrong on those formulas but I use to know it. Not something your average EC needs to know on a daily basis.
I guess Larry is a good judge of character.
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My brain hurts
My brain hurts
Acceleration of gravity is 9.8 m/s^2
After that I'm looking stuff up. Life is open book.
This stuff is hard to talk about. Permittivity changes in free space versus air, which makes 'k' a bit higher. Kinda like when something is off the earth's surface and mass is less affected by gravity's acceleration, so weight is less.
Also, all the super script and subscript stuff is a pain online. And forget Greek letters here. Who is the cruel task master asking you to solve a Coulomb's problem, a physics class?
k = 9.0 x 10^9 Nm^2/C^2
k is a constant, C is a charge (sometimes expressed as Q)
K can also be;
k = 1/(4 x 3.141 x epsilon-o)
where epsilon-o = 8.85 x 10^-12C^2/(Nm^2)
Now use the constant 'k';
Electric Force = F = k(q1q2/r^2)
Where q1 is a +ion, and q2 is a -ion, and r the distance between them.
I don't know about no avocado numbers or oily numbers, they don't have any value to me - presently.
My brain hurts
Acceleration of gravity is 9.8 m/s^2
After that I'm looking stuff up. Life is open book.
This stuff is hard to talk about. Permittivity changes in free space versus air, which makes 'k' a bit higher. Kinda like when something is off the earth's surface and mass is less affected by gravity's acceleration, so weight is less.
Also, all the super script and subscript stuff is a pain online. And forget Greek letters here. Who is the cruel task master asking you to solve a Coulomb's problem, a physics class?
k = 9.0 x 10^9 Nm^2/C^2
k is a constant, C is a charge (sometimes expressed as Q)
K can also be;
k = 1/(4 x 3.141 x epsilon-o)
where epsilon-o = 8.85 x 10^-12C^2/(Nm^2)
Now use the constant 'k';
Electric Force = F = k(q1q2/r^2)
Where q1 is a +ion, and q2 is a -ion, and r the distance between them.
I don't know about no avocado numbers or oily numbers, they don't have any value to me - presently.
Last edited:
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