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sankalpmittal

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In summary: Yes, applying certain mathematical deductions. Come on people. sankalpmittal asked a very simple question about basic electrostatics with macroscopic objects. Why are you talking about quantum effects?

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sankalpmittal

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VihariP

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for more information I suggest feynman lectures chapter Basic forces

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sankalpmittal said:

Not necessary if there are "assistance" from others. Look up "Cooper pairs" in superconductors.

Zz.

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sankalpmittal

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VihariP said:

for more information I suggest feynman lectures chapter Basic forces

Not necessary if there are "assistance" from others. Look up "Cooper pairs" in superconductors.

Zz.

Suppose there is body A and body B of same size and both are having negative charge . They are separated by the distance of less than 35 cm . If body B has thrice the more quantity of charge as body A , will body B and A attract each other ?

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Naty1

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Suppose there is body A and body B of same size and both are having negative charge . They are separated by the distance of less than 35 cm . If body B has thrice the more quantity of charge as body A , will body B and A attract each other ?

Unsure what "attract" means...but typical like charge is repulsive

Not under normal cirumstances, but I can think of a few abnormal ones where they could attract:

They are quantum particles and therefore anything that can happen will happen,

They are rocketing towards each other at high velocity,

They are weakly charged but massive, like black holes, so gravitational attraction will easily overcome weak electrical repulsion...etc,etc

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Naty1

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You might find Wikipedia's discussion of "charge" helpful:

http://en.wikipedia.org/wiki/Charge_(physics )

http://en.wikipedia.org/wiki/Charge_(physics )

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sankalpmittal

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Naty1 said:Unsure what "attract" means...but typical like charge is repulsive

Not under normal cirumstances, but I can think of a few abnormal ones where they could attract:

They are quantum particles and therefore anything that can happen will happen,

They are rocketing towards each other at high velocity,

They are weakly charged but massive, like black holes, so gravitational attraction will easily overcome weak electrical repulsion...etc,etc

But what i have deducted a theory is this :

F=Q*Q*R/T*D

where d is displacement and T is time .Hence in case of body B The force of repulsion to body A is 3 times more . Hence it will repel body A (the whole body ) so the displacement would also increase three times ie not less than 105 cm . So they cannot be attracted to each other , maybe .

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Superstring

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sankalpmittal said:But what i have deducted a theory is this :

F=Q*Q*R/T*D

where d is displacement and T is time .

Hence in case of body B The force of repulsion to body A is 3 times more . Hence it will repel body A (the whole body ) so the displacement would also increase three times ie not less than 105 cm . So they cannot be attracted to each other , maybe .

Not only is that not dimensionally correct, it doesn't even make sense. How did you come up with that?

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sankalpmittal

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Superstring said:Not only is that not dimensionally correct, it doesn't even make sense. How did you come up with that?

BY applying certain mathematical deductions .

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DrZoidberg

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Of course two equally charged objects can attract under the right conditions.

The same goes for magnets btw. If you take a strong magnet and a weak magnet and bring their north poles together, they will attract.

Lets say you have 2 Objects - A and B. A is charged negatively and B is neutral. Now A will attract B. But what happens if you add a single electron to B? Then B will be charged but its charge will be so incredible small that it couldn't possibly change anything. So they still attract. If you keep adding electrons to B the attraction gets smaller and smaller and eventually turns into a repulsion.

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DrZoidberg said:Lets say you have 2 Objects - A and B. A is charged negatively and B is neutral. Now A will attract B.

Using "basic electrostatics", as you said, can you show mathematically how A can actually attract B?

Zz.

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sshzp4

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lol. Which one of you is planning on becoming a professor?

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Kahlua

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Anyway, several of the answers point out when it can happen:

1. On a nuclear level, the nuclear forces overcome the electromagnetic forces on short distances. Equal charges still repel but this force is then small compared to the the attractive nuclear force.

2. Equal charges can be shown to attract as a result of some rather amazing quantum phenomena. In superconductors electrons form bound pairs because they exchange phonons - or, in other words, both interact with the lattice vibrations of a compound in a coherent way so that the net effect is an attraction. This attraction is somewhat abstract though since it is best understood in k and w space and more like a ring dance in ordinary space. A number of other mechanism can be shown to give attraction between charges, e.g. electrons. These electrons are then best understood as "pseudo particles", ordinary electrons with "dressed" properties so that they don't quite behave like ordinary electrons. The dressed properties can come from spin and magnetic interactions, polarizable media, dimensionality aspects, lattice vibrations etc - anything that can be excited and interact with the electrons in a coherent way. Often one refers to magnons, spinons, phonons, plasmons, anyons, holons when discussing such interactions. Some of these have been seen clearly in experiments and some just exist in theory. For more than 20 years scientists have been searching for the mechanism that make electrons "attract" in high temperature superconductor, but this mechanism is still not understood even though it is clearly seen in experiments!

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sankalpmittal

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Superstring said:Not only is that not dimensionally correct, it doesn't even make sense. How did you come up with that?

DrZoidberg said:

Of course two equally charged objects can attract under the right conditions.

The same goes for magnets btw. If you take a strong magnet and a weak magnet and bring their north poles together, they will attract.

Lets say you have 2 Objects - A and B. A is charged negatively and B is neutral. Now A will attract B. But what happens if you add a single electron to B? Then B will be charged but its charge will be so incredible small that it couldn't possibly change anything. So they still attract. If you keep adding electrons to B the attraction gets smaller and smaller and eventually turns into a repulsion.

ZapperZ said:Using "basic electrostatics", as you said, can you show mathematically how A can actually attract B?

Zz.

sshzp4 said:lol. Which one of you is planning on becoming a professor?

Kahlua said:

Anyway, several of the answers point out when it can happen:

1. On a nuclear level, the nuclear forces overcome the electromagnetic forces on short distances. Equal charges still repel but this force is then small compared to the the attractive nuclear force.

2. Equal charges can be shown to attract as a result of some rather amazing quantum phenomena. In superconductors electrons form bound pairs because they exchange phonons - or, in other words, both interact with the lattice vibrations of a compound in a coherent way so that the net effect is an attraction. This attraction is somewhat abstract though since it is best understood in k and w space and more like a ring dance in ordinary space. A number of other mechanism can be shown to give attraction between charges, e.g. electrons. These electrons are then best understood as "pseudo particles", ordinary electrons with "dressed" properties so that they don't quite behave like ordinary electrons. The dressed properties can come from spin and magnetic interactions, polarizable media, dimensionality aspects, lattice vibrations etc - anything that can be excited and interact with the electrons in a coherent way. Often one refers to magnons, spinons, phonons, plasmons, anyons, holons when discussing such interactions. Some of these have been seen clearly in experiments and some just exist in theory. For more than 20 years scientists have been searching for the mechanism that make electrons "attract" in high temperature superconductor, but this mechanism is still not understood even though it is clearly seen in experiments!

First contradict this :

But what i have deducted a theory is this :

F=Q

where d is displacement and T is time .

If charge is 3 times more in body B then

Hence in case of body B The force of repulsion to body A is 9 times more . Hence it will repel body A (the whole body ) so the displacement would also increase nine times ie not less than 325 cm . So they cannot be attracted to each other , maybe because body b will instantaneously repel whole mass of body A .

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Drakkith

Mentor

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Does this count as a yes to the OP's question?

Note that this only occurs in objects that are large enough to be able to have charge seperation. Small objects and particles cannot.

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Superstring

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sankalpmittal said:First contradict this :

But what i have deducted a theory is this :

F=Q^{2}R/T*D

I already did. That equation doesn't have agreeing units - the left side is units of force, and the right side is in charge

Also, you never explained what you mean by "T is time." Time of what? The time between what two events? You never explained what "R" is supposed to represent either.

Explain how you came up with that (absurd) equation, detailing your logical process.

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sankalpmittal said:First contradict this :

But what i have deducted a theory is this :

F=Q^{2}R/T*D

where d is displacement and T is time .

If charge is 3 times more in body B then

Hence in case of body B The force of repulsion to body A is 9 times more . Hence it will repel body A (the whole body ) so the displacement would also increase nine times ie not less than 325 cm . So they cannot be attracted to each other , maybe because body b will instantaneously repel whole mass of body A .

Please note that, if you're making things up on your own, you are making speculative post, and in violation of the https://www.physicsforums.com/showthread.php?t=414380" that you had agreed to.

We will let you continue with this thread if there are indications that you wish to learn. You can show this by addressing the issues brought up by Superstring. However, if you continue to produce your own "deductions", this thread will end!

Zz.

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sankalpmittal

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ZapperZ said:Please note that, if you're making things up on your own, you are making speculative post, and in violation of the https://www.physicsforums.com/showthread.php?t=414380" that you had agreed to.

We will let you continue with this thread if there are indications that you wish to learn. You can show this by addressing the issues brought up by Superstring. However, if you continue to produce your own "deductions", this thread will end!

Zz.

I was just making myself satisfied if the deduction is correct .

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sankalpmittal said:I was just making myself satisfied if the deduction is correct .

But you ignored the obvious mistakes that have been pointed out!

Zz.

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sankalpmittal

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Superstring said:I already did. That equation doesn't have agreeing units - the left side is units of force, and the right side is in charge^{2}per second. The units don't agree.

Also, you never explained what you mean by "T is time." Time of what? The time between what two events? You never explained what "R" is supposed to represent either.

Explain how you came up with that (absurd) equation, detailing your logical process.

F=Q

where d is displacement and T is time .

If charge is 3 times more in body B then

Hence in case of body B The force of repulsion to body A is 9 times more . Hence it will repel body A (the whole body ) so the displacement would also increase nine times ie not less than 325 cm . So they cannot be attracted to each other , maybe because body b will instantaneously repel whole mass of body A .

T represents the time taken by electrons on body A to repel to opposite extreme ends . R is the resistance faced by the e

My deductions however may be wrong .

I never ignored my obvious mistakes . I never said my deductions have to be correct .ZapperZ said:But you ignored the obvious mistakes that have been pointed out!

Zz.

I confess , it may be wrong .

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Drakkith

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sankalpmittal said:I never ignored my obvious mistakes . I never said my deductions have to be correct .

I confess , it may be wrong .

You can't ask someone to refute your math after they've told you it doesn't even make sense and then claim to NOT be ignoring it!

Especially when you haven't show HOW you came to use that equation. I'm sorry but answering "By applying certain mathematical deductions" doesn't tell anyone anything.

You could try using basic electromagnetic formulas that are already available instead of coming up with something on your own.

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Superstring

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sankalpmittal said:F=Q^{2}R/T*D

where d is displacement and T is time .

If charge is 3 times more in body B then

Hence in case of body B The force of repulsion to body A is 9 times more . Hence it will repel body A (the whole body ) so the displacement would also increase nine times ie not less than 325 cm . So they cannot be attracted to each other , maybe because body b will instantaneously repel whole mass of body A .

T represents the time taken by electrons on body A to repel to opposite extreme ends . R is the resistance faced by the e^{-1}while moving to the extreme ends .(different in different materials )

My deductions however may be wrong .

I never ignored my obvious mistakes . I never said my deductions have to be correct .

I confess , it may be wrong .

I may be wrong, but I think I'm correct in assuming that you are probably : a) a troll, b) very young, c) someone with little to no physics education, or d) some combination of the above.

You don't seem to understand the concept of dimensional analysis, and you still have yet to explain how you came up with that equation.

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sankalpmittal

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Superstring said:I may be wrong, but I think I'm correct in assuming that you are probably : a) a troll, b) very young, c) someone with little to no physics education, or d) some combination of the above.

You don't seem to understand the concept of dimensional analysis, and you still have yet to explain how you came up with that equation.

I am in class 10th and this topic must be of class 12th or 11th .

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sankalpmittal said:I never ignored my obvious mistakes . I never said my deductions have to be correct .

I confess , it may be wrong .

You did ignore his remarks. That's why he REPEATED them! You never once addressed the fact that DIMENSIONALLY, your "equation" is wrong!

Zz.

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1. You have never explained what

2. It is contrary to the well-known Coulomb's Law that gives the force between two point charges:

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sankalpmittal

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Here is all the explanation of the equation :Redbelly98 said:

1. You have never explained whatRis. OrFfor that matter, though we all assumeFis the force between two charges.

2. It is contrary to the well-known Coulomb's Law that gives the force between two point charges:

F=Q

where d is displacement and T is time .

If charge is 3 times more in body B then

Hence in case of body B The force of repulsion to body A is 9 times more . Hence it will repel body A (the whole body ) so the displacement would also increase nine times ie not less than 325 cm . So they cannot be attracted to each other , maybe because body b will instantaneously repel whole mass of body A .

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- #27

sankalpmittal

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ZapperZ said:You did ignore his remarks. That's why he REPEATED them! You never once addressed the fact that DIMENSIONALLY, your "equation" is wrong!

Zz.

Rather , when did i say that my equation is correct ??

It is wrong , i admit .

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newtant

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So, if a body is greatly charged(has a greater free elec. charge density than the other) than the other, it can induce opposite charges on the less (charge) dense body. And, a net attractuion between them can take place.

A and B have same size and shape and material. But, suppose A has 2 mole free elec but B has .25 mole free elec, the elec of A can "effectively" push the not so many electrons of B to the other size hence creating a greater distance between negative chareges, and a smaller distance between neg charge of A and +ve charged atoms of B, and net attartction will result. ;P

I wish i kjnew how to DRAW it here.

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Drakkith

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sankalpmittal said:Rather , when did i say that my equation is correct ??

It is wrong , i admit .

It was implied when you asked someone to refute it AFTER it was said that the equation didn't make sense. Anyways, could you not use coloumbs law or something similar?

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sankalpmittal

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Drakkith said:It was implied when you asked someone to refute it AFTER it was said that the equation didn't make sense. Anyways, could you not use coloumbs law or something similar?

yes , of course coloumbs law can be used to identify attraction/repulsion between the two charges . The equation i made was also for the purpose similar to coloumbs law .It may be wrong if visualized dimensionally . Its still better to use coloumbs law as it is proved , isn't it ??

Anyways , from which country are you and what is your age ?Well I'm from India and I study in class 10th .

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sankalpmittal

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newtant said:

So, if a body is greatly charged(has a greater free elec. charge density than the other) than the other, it can induce opposite charges on the less (charge) dense body. And, a net attractuion between them can take place.

A and B have same size and shape and material. But, suppose A has 2 mole free elec but B has .25 mole free elec, the elec of A can "effectively" push the not so many electrons of B to the other size hence creating a greater distance between negative chareges, and a smaller distance between neg charge of A and +ve charged atoms of B, and net attartction will result. ;P

I wish i kjnew how to DRAW it here.

Yeah .

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mrspeedybob

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It seems like the fluid would act as a false neutral. A would have a charge of -1 compared to the fluid and B would have a charge of +1 compared to the fluid so A and B should attract.

Another way to think of this would be to say that object B experiences electrostatic repulsion from the fluid, this repulsion is less in the direction of object A since A displaces some fluid and replaces it with a volume of lower charge. Also The fluid is more highly repulsed from object B then object A is, therefore the fluid moves to the opposite side of object A from object B displacing A and forcing it toward B.

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Drakkith

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- #34

newtant

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- #35

Drakkith

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Your analogy is incorrect. Greed is mutually repulsive in this example. Nothing is induced anywhere.

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