Magnitude of Electric field using superposition principle

In summary: I am getting these from my textbook, and I am not sure if I am doing them correctly.In summary, the electric field at point P is 2740 N/C.
  • #1
skibum143
112
0

Homework Statement



Two charges, +q and -q, are located in the x-y plane at points (0,+d/2) and (0,-d/2), respectively. Calculate the magnitude of the electric field at point P with the superposition principle.
Data: q=37.0 nanoCoulombs,
d=4.60mm and P at
x=92.0mm.

Homework Equations


E = kQ/r^2
a^2 + b^2 = c^2
sin = o/h


The Attempt at a Solution


I tried to solve this like a normal E field question.
For the +q charge, I got that the E field would be:
( k * -37E-6 (sin2) / .092^2) + ( k * 37E-6 (cos2)
and For the -q charge, I got that the E field would be:
( ( k * -37E-6 (sin2) / .092^2) - ( k * 37E-6 (cos2)
This came out to 2740 N/C (positive b/c it asks for magnitude) but that was wrong. Can someone tell me where I'm going wrong? I attached the diagram.
 

Attachments

  • prob11a_dipole1.gif
    prob11a_dipole1.gif
    2.5 KB · Views: 737
Physics news on Phys.org
  • #2
I understood what you first did,

you first said that you will break up E= Esintheta + Ecostheta, one thing I noticed that in the equation E=kq/r^2 , you used for r = 0.092 you used the x distance for the point p, I suggest you have another look at your figure :

http://img231.imageshack.us/img231/5466/59813260.gif [Broken]

compare the blue line with the red one , do you still think that the distance between q and p is x (0.092) ?
 
Last edited by a moderator:
  • #3
When I did (.092^2) + (.0023^2), I get that the hypotenuse is .0092...
 
  • #4
Ah, sorry my mistake, I now get .00847. I will try that. Was the rest of the setup ok? Thanks for your help!
 
  • #5
Hmmm... that was still wrong. Am I doing something else incorrectly?
 
  • #6
i think the required distance between q and p should be sqrt((0.092^2) + (0.0023^2)) i did the calculation and i got 0.092028 (when you said it is 0.00847 you didnt take the square root) ..

another thing, I think you probably haven't considered the elecrtic field produced from positive charge and negative charge, have a look at this figure:

http://img402.imageshack.us/img402/7681/95152182.jpg [Broken]

so your problem should look something like the following:

http://img4.imageshack.us/img4/4996/34194234.gif [Broken]

notice where r the electric field vectors , find the components of each vectors ,then see whether you will find any compenents that will cancel with each other and pay attention to the directions ..

by the way , i have one question for you , from where you get sin2 and cos2?
 
Last edited by a moderator:

1. What is the superposition principle in relation to the magnitude of electric field?

The superposition principle states that the total electric field at any point in space is the vector sum of the individual electric fields created by each source charge.

2. How do you calculate the magnitude of electric field using the superposition principle?

To calculate the magnitude of electric field at a point using the superposition principle, you need to add up the individual electric fields created by each source charge at that point. This can be done by using the formula E = kq/r^2, where k is Coulomb's constant, q is the source charge, and r is the distance between the source charge and the point of interest.

3. What factors affect the magnitude of electric field at a point?

The magnitude of electric field at a point is affected by the distance between the source charge and the point, as well as the magnitude of the source charge. Additionally, the presence of other nearby charges can also affect the magnitude of electric field at a point due to the superposition principle.

4. Can the superposition principle be applied to all situations involving electric fields?

Yes, the superposition principle can be applied to all situations involving electric fields as long as the electric charges involved are static (not moving). It is a fundamental principle in electromagnetism and is used in various applications, such as in the design of electronic circuits.

5. How is the superposition principle related to the concept of electric potential?

The superposition principle is closely related to the concept of electric potential. Electric potential is a measure of the potential energy per unit charge at a point in an electric field. The potential at a point is the sum of the potentials due to each source charge at that point, which is analogous to the superposition principle for electric fields.

Similar threads

  • Introductory Physics Homework Help
Replies
5
Views
730
  • Introductory Physics Homework Help
Replies
5
Views
635
  • Introductory Physics Homework Help
Replies
3
Views
733
  • Introductory Physics Homework Help
Replies
2
Views
484
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
32
Views
2K
  • Introductory Physics Homework Help
Replies
11
Views
2K
  • Introductory Physics Homework Help
Replies
17
Views
323
Replies
12
Views
2K
  • Introductory Physics Homework Help
Replies
12
Views
2K
Back
Top