Electric fields, Superposition, and Intervening Matter

AI Thread Summary
Electric fields can penetrate intervening matter, illustrating the superposition principle, which states that the net electric field is the sum of individual fields. When a piece of paper is placed between two like-charged pieces of tape, it induces dipoles that affect the overall electric field rather than simply blocking it. The induced dipoles in the paper align such that the negative poles face the tape, creating an attractive force that draws the tape toward the paper. This phenomenon highlights the complexity of electric interactions and the role of superposition in understanding them. The discussion emphasizes the need for a clearer visualization of how induced dipoles influence electric fields in the presence of intervening materials.
johns120
Messages
2
Reaction score
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"
 
Last edited by a moderator:
Physics news on Phys.org
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.
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top