Is it possible that the two bodies having same charge attract each other ?

[sankalpmittal]

I have read in one book that it is possible if one body possesses greater similar charge than other .

 

[VihariP]

yes it is possible but not of bodies of everyday size. The nuclear force is what make them do that, and it is dominant over coloumbic only when the distance is less than some threshold as in atoms. This force is effect of release of energy because of reduced mass resulting when nucleons come together. Recent research says they are the result of sharing mesons between nucleons.
for more information I suggest feynman lectures chapter Basic forces

 

[ZapperZ]

I have read in one book that it is possible if one body possesses greater similar charge than other .

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

Zz.

 

[sankalpmittal]

yes it is possible but not of bodies of everyday size. The nuclear force is what make them do that, and it is dominant over coloumbic only when the distance is less than some threshold as in atoms. This force is effect of release of energy because of reduced mass resulting when nucleons come together. Recent research says they are the result of sharing mesons between nucleons.
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 ?

 

[Naty1]

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

 

[Naty1]

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

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

 

[sankalpmittal]

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 .

 

[Superstring]

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?

 

[sankalpmittal]

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 .

 

[DrZoidberg]

Come on people. sankalpmittal asked a very simple question about basic electrostatics with macroscopic objects. Why are you talking about quantum effects?
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]

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.

 

[sshzp4]

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

 

[Kahlua]

I'm interested which book you read that in.
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!

 

[sankalpmittal]

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

Come on people. sankalpmittal asked a very simple question about basic electrostatics with macroscopic objects. Why are you talking about quantum effects?
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.

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

Zz.

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

I'm interested which book you read that in.
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=Q²R/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 .

 

[Drakkith]

Hrmm. I'd See here: http://en.wikipedia.org/wiki/Electrostatic_induction
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.

 

[Superstring]

First contradict this :
But what i have deducted a theory is this :
F=Q²R/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 charge² 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.

 

[ZapperZ]

First contradict this :
But what i have deducted a theory is this :
F=Q²R/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.

 

[sankalpmittal]

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 .

 

[ZapperZ]

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

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

Zz.

 

[sankalpmittal]

I already did. That equation doesn't have agreeing units - the left side is units of force, and the right side is in charge² 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=Q²R/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 .

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

Zz.

I never ignored my obvious mistakes . I never said my deductions have to be correct .
I confess , it may be wrong .

 

[Drakkith]

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.

 

[Superstring]

F=Q²R/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.

 

[sankalpmittal]

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 .

 

[ZapperZ]

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.

 

[Redbelly98]

sankalpmittal, here are two problems people are having with your equation:

1. You have never explained what R is. Or F for that matter, though we all assume F is the force between two charges.
2. It is contrary to the well-known Coulomb's Law that gives the force between two point charges:

http://en.wikipedia.org/wiki/Coulomb's_law#Basic_equation​

 

[sankalpmittal]

sankalpmittal, here are two problems people are having with your equation:

1. You have never explained what R is. Or F for that matter, though we all assume F is the force between two charges.
2. It is contrary to the well-known Coulomb's Law that gives the force between two point charges:

http://en.wikipedia.org/wiki/Coulomb's_law#Basic_equation​

Here is all the explanation of the equation :
F=Q²R/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 )

 

[sankalpmittal]

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 .

 

[newtant]

I am sorry i didnt have the time to read all of yours answerss to if it is already answered, just jump over my answer.

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.

 

[Drakkith]

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?

 

[sankalpmittal]

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 .

 

[sankalpmittal]

I am sorry i didnt have the time to read all of yours answerss to if it is already answered, just jump over my answer.

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 .

 

[mrspeedybob]

Suppose you have 2 objects suspended in a fluid, both objects and the fluid have the same density. The fluid is non-conductive and extends far enough away from both objects in all directions that its edge is irrelevant. Object A has a charge density of +1 coulomb per unit volume, the fluid has a charge density of +2 coulombs per unit volume, and object B has a charge density of +3 coulomb per unit volume.

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.

 

[Drakkith]

Bob, even if that does work it doesn't mean A and B are attracting each other. They are simply being pushed together.

 

[newtant]

we can also draw an analogy. Suppose we have 3 guys. You can increase it to any number. Say, 1 guy has so so much money. The other has a small amount of money. Person 3 has zero money. 1 can induce greed in person 2 and 3. Person 2 can induce greed in only person 3. Person 3 can't induce **** lol. So now say greed is equal to attracting. I hope this was clear and simple. I personally think physics is one subject that has endless analogies that can be drawn.

 

[Drakkith]

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

 

[Born2bwire]

Suppose you have 2 objects suspended in a fluid, both objects and the fluid have the same density. The fluid is non-conductive and extends far enough away from both objects in all directions that its edge is irrelevant. Object A has a charge density of +1 coulomb per unit volume, the fluid has a charge density of +2 coulombs per unit volume, and object B has a charge density of +3 coulomb per unit volume.

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.

This is a good point to keep in mind. We often assume the mindset of the vacuum as being our background in many problems. But if we allow for some interstitual medium we can get results that are contrary to our initial feelings. We can get like charged bodies to attract. Likewise, in van der Waals and Casimir forces we can get objects that would normally attract to repulse through judicious choice of our background medium.

Anyway, I believe this is outside of what the OP was asking about. It seems that the OP is assuming that there can be a time lag in the distribution of the charges on the objects in response to the applied field of the other. He seems to posit that the time lag could result in a charge distribution that would momentarily allow for attraction and if this attraction is strong enough can cause an avalanche effect that continually reinforces the attraction.

However, I too will contend that his equation is incorrect by the simple basis of incorrect units and dimensional analysis. He contends that:

F = Q^2*R/(T*D)

However, we already know that

F = k*Q^2/D

(To use his standard of notation) where k is in units of H/m. I know of no process by which you can argue that ohm/sec is equivalent to H/m and thus his equation fails.

Nor do I think that the OP's conceptual theory works either. Still, to properly analyze this phenomenon he cannot use electrostatics but must use electrodynamics because the reorganization of charges on the objects would be currents. Thus you would have electromagnetic fields to contend with in the analysis.

 

[sankalpmittal]

Bob, even if that does work it doesn't mean A and B are attracting each other. They are simply being pushed together.

That is what i was trying to conclude .

If there are two bodies A and B :

1. A possesses X unit of charge.
2. B possesses 3X unit of charge .

Then How can these two bodies attract ??


Body B will repel whole mass of body A in flick of a second before induction takes place .

 

[Dadface]

Looking at the original question I think the answer is yes and I think the reasoning for this was given most elegantly by DrZoidberg in post number ten.If anyone is unable to see this,then extend DrZoidbergs scenario further by having the body with the single excess electron having an enormous size and the second body having a very small size.In principle that single electron could be separated from the small body by distances tending to infinity.

 

[Dadface]

That is what i was trying to conclude .

If there are two bodies A and B :

1. A possesses X unit of charge.
2. B possesses 3X unit of charge .

Then How can these two bodies attract ??


Body B will repel whole mass of body A in flick of a second before induction takes place .

Why should they attract? For attraction the charge ratio is likely to be much greater than three to one.

 

[cragar]

what if we had 2 black holes that had the same charge and their gravitational attraction over came the repulsion.

 

[Superstring]

what if we had 2 black holes that had the same charge and their gravitational attraction over came the repulsion.

Isn't the electrostatic force carried by photons which can't escape the hole in the first place (by definition)?

 

[cragar]

I thought a BH could have 3 properties and one of them is charge. I thought when an electron crosses the event horizon its Electric field will be frozen in outside the event horizon.
http://en.wikipedia.org/wiki/Charged_black_hole
And if that doesn't work I still think we might be able to have 2 very large masses that have very little charge that could gravitationally attract that weren't black holes. Maybe.

 

[Drakkith]

I think we are getting off track here. I thought the question was all related to the attraction and repulsion due to the electromagnetic fields. Otherwise the issue is pretty moot.

 

[Cbray]

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 ?

How can two masses have different charges? (Not going against, just new to physics).

 

[sankalpmittal]

How can two masses have different charges? (Not going against, just new to physics).

In case of static electricity suppose a body A is positively charged and other body B is neutral .
Then you bring body A close to body B . Since body A is having deficiency of electrons it will attract electrons towards itself from opposite extreme end of body B . This end acquires negative charge while other positive . opposite end has less powerful bond and loses negative charge to atmosphere or Earth .Or if you rub comb with hair then comb acquires positive charge while hairs negative ( depending on electrification series )
In which class are you and from which country ?
I am in class 10th , 14 years from India .

 

[Cbray]

In case of static electricity suppose a body A is positively charged and other body B is neutral .
Then you bring body A close to body B . Since body A is having deficiency of electrons it will attract electrons towards itself from opposite extreme end of body B . This end acquires negative charge while other positive . opposite end has less powerful bond and loses negative charge to atmosphere or Earth .


Or if you rub comb with hair then comb acquires positive charge while hairs negative ( depending on electrification series )



In which class are you and from which country ?
I am in class 10th , 14 years from India .

Sorry I didn't notice that it was due to static electricity.

I'm in Year 9, 14 years old from Australia :)

 

[sankalpmittal]

Sorry I didn't notice that it was due to static electricity.

I'm in Year 9, 14 years old from Australia :)

You are in class 9th ??and 14 years !Hey I am also 14 years in class 10th .

Do classes in Australia start from 6 years or something ? :D

 

[Cbray]

You are in class 9th ??and 14 years !Hey I am also 14 years in class 10th .

Do classes in Australia start from 6 years or something ? :D

Kindergarten - Year 6 (Primary School). Year 7 - 10 (High school). Year 11 - 12 (College). Then University.

 

[sankalpmittal]

Kindergarten - Year 6 (Primary School). Year 7 - 10 (High school). Year 11 - 12 (College). Then University.

In India :
Kindergarten- Year 5(Primary School). Year 6-8(Middle School) . Year 9-10 (High School or secondary school) . Year 11-12 (College or senior secondary)

Then degree colleges or universities .

 

[Superstring]

In India :
Kindergarten- Year 5(Primary School). Year 6-8(Middle School) . Year 9-10 (High School or secondary school) . Year 11-12 (College or senior secondary)

Then degree colleges or universities .

This is extremely off-topic.