Electric fields, Superposition, and Intervening Matter

In summary, the conversation discusses the superposition principle and its application to the repulsion between two like-charged pieces of tape when a piece of paper is placed between them. The reduction in repulsion is not due to the paper blocking the electric field, but rather the superposition of two fields: the original field and another field due to induced dipoles in the paper. The conversation also mentions the confusion about the direction of the induced dipoles and how the superposition principle explains this phenomenon.
  • #1
johns120
2
0
So my physics textbook briefly mentions

The fact that an electric field acts through intervening matter is another example of the superposition principle. It is true that the
repulsion between two like-charged pieces of tape is weaker when a piece of paper is in the way (Experiment 15.EXP.22), but when
viewed in terms of the superposition principle this reduction is not due to the paper partially “blocking” the field of the other tape.
Rather, we say that the net field is due to the superposition of two fields: the same field that you would have had without the paper
intervening, plus another field due to the induced dipoles in the paper.

What I don't understand is: If the paper is put between the charges, those charges would induce a dipole, right? Since there are charges on both sides and "like-charged" which way would the dipole point. The book says the tape is attracted to the paper (which your left to infer creates a force pulling each piece of tape in towards the paper) I just can't visualize how this is possible and I certainly don't understand what the superposition principle has to do with it. https://www.physicsforums.com/attachment.php?attachmentid=39236&d=1316902478"
 
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  • #2
Just a guess. Maybe the dipoles nearer to the left surface of the paper will have the negative poles to the left, and the dipoles nearer to the right surface of the paper will have the negative poles to the right.
 

Related to Electric fields, Superposition, and Intervening Matter

1. What is an electric field?

An electric field is a region in space surrounding an electrically charged particle or object. It exerts a force on other charged particles or objects within the field, either attracting or repelling them depending on the direction of the field.

2. How is superposition related to electric fields?

Superposition is the principle that states when multiple electric fields are present in a given space, the combined field at any point is the vector sum of the individual fields. This means that the electric field at a point is the sum of the fields from each individual charged particle or object in the vicinity.

3. How does intervening matter affect electric fields?

Intervening matter, such as a dielectric or insulator, can alter the strength and direction of an electric field. It can either enhance or reduce the field depending on its properties and the arrangement of the charged particles or objects within it.

4. What is the relationship between electric fields and electric potential?

Electric potential is a measure of the electric potential energy per unit charge at a given point in an electric field. It is directly proportional to the strength of the electric field and can be used to calculate the work done by the field on a charged particle as it moves from one point to another.

5. How can electric fields be applied in real-life situations?

Electric fields have numerous practical applications, including in electronic devices, power generation and distribution, and medical equipment. They can also be used for electrostatic separation, particle accelerators, and controlling the motion of charged particles in vacuum tubes or plasma. Additionally, electric fields play a crucial role in many natural phenomena, such as lightning and the Earth's magnetic field.

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