What is the net charge and why does it matter?

[sophiecentaur]

Thank you for the reply, Sir. Please behave well. I may be wrong anywhere, explain why I am wrong. Instead don't use rude language.

What "rude language"? Are you offended by the Inverted Commas?
I am asking a very short and straightforward question. If you can't answer it then you need to rethink your ideas.

 

[Doc Al]

Thank you for the reply, Sir. Please behave well. I may be wrong anywhere, explain why I am wrong. Instead don't use rude language.

Why don't you just answer the question? No one's being rude. (And your error has been explained several times over!)

 

[CURIE WILLEY]

@DOC AL. Thank you for the reply, Sir. If we have +1 charge in one hand and -1 charge in the other hand, net charge will not be zero (as distance of separation is not zero). In that case, according to me, we need to calculate the electric field created by that dipole at any point, which is at distance r from the center of dipole (we can calculate this from the equation I have given at the begining). By substituting the obtained values of r and E in the electric field produced by a charge equation, we get q value (i.e net charge).

Here, I am not arguing myself to be correct. I am just clarifying my doubts. If I have not behaved well anywhere, pardon me. I will be replying until I get satisfactory result. You may be correct, but I may not be getting your ideas. I hope you will answer me, until I get clarified. Thank you.

 

[sophiecentaur]

@DOC AL. Thank you for the reply, Sir. If we have +1 charge in one hand and -1 charge in the other hand, net charge will not be zero (as distance of separation is not zero). In that case, according to me, we need to calculate the electric field created by that dipole at any point, which is at distance r from the center of dipole (we can calculate this from the equation I have given at the begining). By substituting the obtained values of r and E in the electric field produced by a charge equation, we get q value (i.e net charge).

Here, I am not arguing myself to be correct. I am just clarifying my doubts. If I have not behaved well anywhere, pardon me. I will be replying until I get satisfactory result. You may be correct, but I may not be getting your ideas. I hope you will answer me, until I get clarified. Thank you.

OK, that is your problem. Charge is not a function of position. You are still hanging in on to that statement you started the thread with, which is incorrect. Saying you read it on Wiki, is no justification for it. You will need to let that go, I'm afraid. or launch down your own road towards a different version of Physics. PF will not be following you there.

You are trying to apply blind logic to a faulty premise. You need a more reasonable approach or you will get nowhere.

 

[Cthugha]

@DOC AL. Thank you for the reply, Sir. If we have +1 charge in one hand and -1 charge in the other hand, net charge will not be zero (as distance of separation is not zero).

That does not matter. Draw a circle around your system and count all the charges inside. The number you get is your net charge and here it is zero. The position or separation does NOT matter. This is your very own definition nobody else uses. You cannot expect people to help you if you make up your own language.

 

[Ahsan Khan]

According to you, if the system is neutral, still there can be electric field around it. Isn't it,sir?

According to me, if the system is neutral, there exists no electric field around it.

Wrong. A system of charge may or may not have an electric field around it. As said charge is the exclusive property of (certain) sub-atomic particles not a property of matter in bulk. Charge is such a fundamental property that you can not remove or add this property to anything, what you can only do is to transfer the charge to it other bodies and we say it is charged or toned with or filled with charge. The body just have charge(sub-atomic) particles but itself doesn't become charge(or a collection of charge) as the definition of charge fits only for (certain) sub-atomic particles(like electron and proton).

Accrding to coulombs law, force between the charges is given by the equation

$F=\frac{1}{4∏ε}.\frac{q_1q_2}{r^2}$

If $q_2$ has net charge zero, it can't exert force on other charge according to me, because it has no electric field around it.

Coulombs law is valid only for point charges not for group of charges.

 

[CURIE WILLEY]

@DOC AL. Thank you for the reply, Sir. If we have +1 charge in one hand and -1 charge in the other hand, net charge will not be zero (as distance of separation is not zero). In that case, according to me, we need to calculate the electric field created by that dipole at any point, which is at distance r from the center of dipole (we can calculate this from the equation I have given at the begining). By substituting the obtained values of r and E in the electric field produced by a charge equation, we get q value (i.e net charge).

Here, I am not arguing myself to be correct. I am just clarifying my doubts. If I have not behaved well anywhere, pardon me. I will be replying until I get satisfactory result. You may be correct, but I may not be getting your ideas. I hope you will answer me, until I get clarified. Thank you.

I must add here, as sophiecentaur Sir noted, we can see that for different value of r, we get different value of net charge. For the observer at infinity, net charge of the system will be zero. For the observer near the system the net charge will be maximum.

 

[Ahsan Khan]

What is electric charge?
Electric charge is the physical property of matter that causes it to experience a force when close to other electrically charged matter.

Wrong. I guessed here the key problem is your wrong understanding about the fundamental of charge. Charge not the property of matter(in bulk) it is the property of(certain)sub-atomic particles(like,electron, proton etc). Charge is not a substance rather it is property of certain sub-atomic particles just as mass is the property of any matter charge is also a property. You can add mass to a body what you only can do is to add matter(having property of mass) so that they get weighed. But by doing this you can not call matter as mass matter and mass is different. And definition of mass should not be applied to matter in any case.

So, if the particle has electric charge, there is an electric field around it.

Yes offcourse, but for this it must be a particle(or better I call a sub-atomic particle like electron).

 

[CURIE WILLEY]

OK, that is your problem. Charge is not a function of position.You are still hanging in on to that statement you started the thread with, which is incorrect. Saying you read it on Wiki, is no justification for it. You will need to let that go, I'm afraid. or launch down your own road towards a different version of Physics. PF will not be following you there.

Thank you for replying and being cooperative, Sir. As the discussion has followed, definition (charge or neutral particle) of wiki has been said to be wrong. If correct definition is provided, it will be greatly appreciable. This decides whether I am launching a new road towards a different version of Physics or not, or PF will be following me or not.

You are trying to apply blind logic to a faulty premise. You need a more reasonable approach or you will get nowhere.

I will try to bring brightness where there is blind logic, please provide info on where there is blind logic.

 

[Ahsan Khan]

According to me, sum of the charges will always be zero. But, net charge will be zero if and only if distance between the charge is zero. I think there is a distinction between net charge and sum of charge. [/B]

If you think there is a distinction(which you have created by your own and offcourse you can, but society of science has already made these two terms alike and probably they are not going to change for you) then read Gauss Law which talks about net charge enclosed by a body. And it says the flux linked by Gaussian surface is proportional to the NET CHARGE contained in it. And in the calculations to find net charge you just need to take algebraic SUM OF THE CHARGES, distance between them does not affect the net charge.

 

[CURIE WILLEY]

That does not matter. Draw a circle around your system and count all the charges inside. The number you get is your net charge and here it is zero.

I have replied, why I don't agree net charge is zero here. Please read it, if you find I am wrong there, pardon me and explain where I am wrong.

The position or separation does NOT matter. This is your very own definition nobody else uses. You cannot expect people to help you if you make up your own language.

If you think I have created my own definition, please specify which one I have created. And please provide correct definition for it (with reference, from where you have got that definition).

 

[Doc Al]

@DOC AL. Thank you for the reply, Sir. If we have +1 charge in one hand and -1 charge in the other hand, net charge will not be zero (as distance of separation is not zero).

False. Until you correct this statement, there's not much point of going any further. The net charge will be zero regardless of the distance.

 

[Ahsan Khan]

According to coulombs law, force between the charges is given by the equation

$F=\frac{1}{4∏ε}.\frac{q_1q_2}{r^2}$

If $q_2$ has net charge zero, it can't exert force on other charge according to me, because it has no electric field around it.

Yes if q2 is not exerting force then it can never be charged PARTICLE(remember you are saying it on the basic of Coulomb's law which is valid for point charges). But what if this is not a point,sized charged particle but a collection of charged particles(like dipole or hydrogen atom- on which you are trying to apply the definition of charge while they are not charge, for charge is exclusively the property of a(certain sub-atomic) particles you should not apply it for collection of charge))or matter with charge particles.
Do you think Coulomb would allow to use his law under such case?

 

[CURIE WILLEY]

@DOC AL. Thank you for the reply, Sir. If we have +1 charge in one hand and -1 charge in the other hand, net charge will not be zero (as distance of separation is not zero).

False. Until you correct this statement, there's not much point of going any further. The net charge will be zero regardless of the distance.

If distance of separation between the opposite charges of the dipole is zero, electric field around the system will be zero. As said always, according to me, if field is zero, net charge is zero. If distance of separation between the opposite charges is non-zero, there exists field. So, according to me, if field is non-zero, net charge is non-zero.

This has been disagreed, saying definitions of wiki is wrong. If they are wrong, it would be appreciable if correct definitions are provided (with reference, from where that definition has been extracted).

I think we are in need of knowing what actually is net charge?

So, if any particular definition from any particular reference would be appreciable. I have provided my opinion on the basis of wiki, but they are said be incorrect. So, there is a need of knowing correct definitions.

 

[ZapperZ]

Closed, pending moderation.

Zz.

 

[Dale]

This has been disagreed, saying definitions of wiki is wrong. If they are wrong, it would be appreciable if correct definitions are provided (with reference, from where that definition has been extracted).

I think we are in need of knowing what actually is net charge?

The definition of net charge was given by Doc Al in post 10.

Net charge being zero simply means that the total charge (just add 'em up) is zero: \Sigma q_i = 0

For references there are the following academic links:
http://www.physics.sjsu.edu/becker/physics51/elec_charge.htm
http://web.mit.edu/viz/EM/visualizations/coursenotes/modules/guide02.pdf

Although it should be obvious. The term "net" simply means the sum. So your "net income" is the sum of all of your sources of income less any deductions to your income. Similarly, "net force" on an object is the sum of all forces acting on the object. Similarly, "net charge" is the sum of all the charges.

Note that $E=k\Sigma (q_i/r_i^2) \mathbf{\hat r}$ can be non-zero even if $\Sigma q_i$ is zero. Your reasoning is simply wrong, as was pointed out to you many times.