When objects repel each other, one can be certain that both objects are charged. On the other had, the observation of an attractive interaction leads to limited conclusions. At best, one can conclude that at least one of the objects is charged. We'll conclude this part of Lesson 1 by asking the question "How can a charged object and a neutral object attract? Where did this third charge interaction come from?
In all likelihood, most of us have only heard of two types of charge interactions opposites attract and likes repel ; and both of these charge interactions are fundamental interactions. The third statement - any charged object and a neutral object will attract each other - is simply an observable fact that can be explained by the two fundamental charge interactions. The explanation of this third charge interaction will be saved for the last page of Lesson 1.
But first, the subject of conductors and insulators must be explored in order to understand our third type of charge interaction. Use your understanding of charge to answer the following questions. When finished, click the button to view the answers. Electric forces are repulsive for objects of like charge and attractive between objects of the opposite type of charge or between charged objects and neutral objects. On two occasions, the following charge interactions between balloons A, B and C are observed.
In each case, it is known that balloon B is charged negatively. Based on these observations, what can you conclusively confirm about the charge on balloon A and C for each situation. However, A would also attract B if it were neutral. If C repels B, then you know for certain that it has the same type of charge as C - that is, a - charge.
Upon entering the room, you observe two balloons suspended from the ceiling. You notice that instead of hanging straight down vertically, the balloons seems to be repelling each other. You can conclusively say Observing a repulsive interaction is sufficient evidence to conclude that both balloons are charged.
However, further testing or additional information would be required to determine the type of charge the balloons have. Jean knows that object A is negatively charged and object B is electrically neutral. It's best to start on the right side of the table. Since D and E attract, D must have the opposite charge of E. If C has like charge as D, it must be - also. Two objects are charged as shown at the right.
Having the same type of charge, they will repel. Two objects are shown at the right. One is neutral and the other is negative. Balloons X , Y and Z are suspended from strings as shown at the right. Negatively charged balloon X attracts balloon Y and balloon Y attracts balloon Z.
List all that apply. Y is observed to attract a negatively charged object balloon X. So Y could be either positively charged or neutral. Y attracts Z. So A and B are two possible answers. But Y could be positively charged. And if Y were positively charged, the Y-Z attraction would be observed if Z were neutral. So choice C is also possible. Physics Tutorial. Charging by conduction involves the contact of a charged object to a neutral object. Suppose that a positively charged aluminum plate is touched to a neutral metal sphere.
The neutral metal sphere becomes charged as the result of being contacted by the charged aluminum plate. Or suppose that a negatively charged metal sphere is touched to the top plate of a neutral needle electroscope. The neutral electroscope becomes charged as the result of being contacted by the metal sphere. And finally, suppose that an uncharged physics student stands on an insulating platform and touches a negatively charged Van de Graaff generator.
The neutral physics student becomes charged as the result of contact with the Van de Graaff generator. Each of these examples involves contact between a charged object and a neutral object.
In contrast to induction, where the charged object is brought near but never contacted to the object being charged, conduction charging involves making the physical connection of the charged object to the neutral object. Because charging by conduction involves contact, it is often called charging by contact.
To explain the process of charging by contact, we will first consider the case of using a negatively charged metal sphere to charge a neutral needle electroscope.
Understanding the process demands that you understand that like charges repel and have an intense desire to reduce their repulsions by spreading about as far as possible. A negatively charged metal sphere has an excess of electrons; those electrons find each other repulsive and distance themselves from each other as far as possible. The perimeter the sphere is the extreme to which they can go. If there was ever a conducting pathway to a more spacious piece of real estate, one could be sure that the electrons would be on that pathway to the greener grass beyond.
In human terms, electrons living in the same home despise each other and are always seeking a home of their own or at least a home with more rooms. Given this understanding of electron-electron repulsions, it is not difficult to predict what excess electrons on the metal sphere would be inclined to do if the sphere were touched to the neutral electroscope. Once the contact of the sphere to the electroscope is made, a countless number of excess electrons from the sphere move onto the electroscope and spread about the sphere-electroscope system.
In general, the object that offers the most space in which to "hang out" will be the object that houses the greatest number of excess electrons. When the process of charging by conduction is complete, the electroscope acquires an excess negative charge due to the movement of electrons onto it from the metal sphere. The metal sphere is still charged negatively, only it has less excess negative charge than it had prior to the conduction charging process.
The previous example of charging by conduction involved touching a negatively charged object to a neutral object. Upon contact, electrons moved from the negatively charged object onto the neutral object. When finished, both objects were negatively charged. But what happens if a positively charged object is touched to a neutral object?
To investigate this question, we consider the case of a positively charged aluminum plate being used to charge a neutral metal sphere by the process of conduction. The diagram below depicts the use of a positively charged aluminum plate being touched to a neutral metal sphere.
A positively charged aluminum plate has an excess of protons. When looked at from an electron perspective, a positively charged aluminum plate has a shortage of electrons. In human terms, we could say that each excess proton is rather discontented. It is not satisfied until it has found a negatively charged electron with which to co-habitate. However, since a proton is tightly bound in the nucleus of an atom, it is incapable of leaving an atom in search of that longed-for electron.
It can however attract a mobile electron towards itself. And if a conducting pathway is made between a collection of electrons and an excess proton, one can be certain that there is likely an electron that would be willing to take the pathway. So when the positively charged aluminum plate is touched to the neutral metal sphere, countless electrons on the metal sphere migrate towards the aluminum plate. There is a mass migration of electrons until the positive charge on the aluminum plate-metal sphere system becomes redistributed.
Having lost electrons to the positively charged aluminum plate, there is a shortage of electrons on the sphere and an overall positive charge. The aluminum plate is still charged positively; only it now has less excess positive charge than it had before the charging process began. The above explanation might raise a rather difficult question: Why would an electron on the previously neutral metal sphere desire to move off the metal sphere in the first place?
The metal sphere is neutral; every electron on it must be satisfied since there is a corresponding proton present. What would possibly induce an electron to go through the effort of migrating to a different territory in order to have what it already has? The best means of answering this question requires an understanding of the concept of electric potential.
But since that concept does not arise until the next unit of The Physics Classroom , a different approach to an answer will be taken. It ends up that electrons and protons are not as independent and individualized as we might think. From a human perspective, electrons and protons can't be thought of as independent citizens in a free enterprise system of government.
Electrons and protons don't actually do what is best for themselves, but must be more social-minded. They must act like citizens of a state where the rule of law is to behave in a manner such that the overall repulsive affects within the society at large are reduced and the overall attractive affects are maximized.
Electrons and protons will be motivated not by what is good for them, but rather by what is good for the country. And in this sense, a country's boundary extends to the perimeter of the conductor material that an excess electron is within. You have two electrodes, one positively charged and one negatively charged by means of the voltage that you are applying. So, positively charged ions in a solution are attracted electrostatically to the negatively charged electrode where they receive electrons.
And negatively charged ions are attracted electrostatically to the positively charged electrode where they donate electrons. Thus ions return to their uncharged elemental state. Yes, by bringing the positively-charged object near the object to be charged, then discharging the far side.
The traditional explanation is that the positively charged protons electrostatically attract the negatively charged electrons. Electrostatic attraction. A charged object can lose its charge by grounding it moving electrons from a highly charged object to a lowly charged one or by getting like charges from another object.
A charged object is matter that either has a surplus of electrons negatively charged or a deficiency of electrons positively charged. There will be flow of electrons from negatively charged object towards the positively charged object making an attempt to make both of them electrically neutral. A charged object attracts the neutral object by polarising it. A positively charged object. Like charges repel. When an object is charged, it either has a surplus or deficiency of electrons.
If it has a surplus, the object is negatively charged, and if it has a deficiency, then it is positively charged has more protons than electrons.
The charged object may induce a separation of charges in the neutral object. Both the neutral and charged objects have many positively as well as negatively charged particles. In neutral objects the number of the positively charged particles equals the number of negatively charged particles so there is no net charge where as in a charged object either the number of positively charged particles or the number of negatively charged particles is more to correspond for the net charge If an object has an unequal number of protons and electrons, then the object becomes electrically charged.
An object that is positively charged has more protons than electrons. A neutrally charged object can still be affected by a charged object. If a neutrally charged object is being approached by a negatively charged objects, the electrons within the neutrally charged object will migrate to the other side as the two negative charges repel , leaving the side closes to the negative object positive.
Protons do not move. From there, the protons are attracted to the electrons, therefore moving the 'uncharged' object. I assume you mean "neutral object". The answer is that the charged object will induce a separation of charges in the neutral object.
It depends on the type of non-charged object.
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