Electric Field of a dipole

In summary: N/CIn summary, the electric field due to a dipole with charges +q and -q, held apart by a rod of length s, at a location A a distance d away is given by the formula 2qs/4piE*r^3, where E is the permittivity of vacuum. In this problem, with q = 4 nC and s = 2 mm, the magnitude of the electric field at location A, which is on axis with the dipole, is found to be 2.88N/C. However, it was later realized that the value for d needed to be cubed in the formula, resulting in a corrected answer of
  • #1
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Homework Statement


A dipole consists of two charges +q and -q, held apart by a rod of length s, as shown in the diagram. If q = 4 nC and s = 2 mm, what is the magnitude of the electric field due to the dipole at location A, a distance d = 5 cm from the dipole?

The diagram shows point A being on axis with the dipole.

Homework Equations



The formula for on axis is 2qs/4piE*r^3, where E is the permittivity of vacuum

The Attempt at a Solution



So to solve this first I converted all units

q = 4nC = 4e-9C
s = 2mm = .002m
d = 5cm = .05m

Then I plug in the values into the formula

2*4e-9C*.002m/4pi*8.85e-12*.05m = 2.88N/C
But that seems to be the wrong answer can someone please tell me what I'm doing wrong
and also is it true that the field perpendicular to the dipole is just half of what it would be if it was on axis. If that's true than the field 5cm perpendicular to the dipole should be just half of what I come up with, in this case 1.44N/C.

Thank You for your help
 
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  • #2
Oh I think I figured out where I went wrong I forgot to cube d,
 

1. What is an electric dipole?

An electric dipole is a pair of equal and opposite charges separated by a distance, resulting in a net electric charge. It can be thought of as a positive and negative charge that are slightly separated from each other.

2. How is the electric field of a dipole calculated?

The electric field of a dipole can be calculated using the formula E = kqd/r^3, where k is the Coulomb's constant, q is the magnitude of the charge, d is the distance between the charges, and r is the distance from the center of the dipole to the point where the electric field is being measured.

3. What is the direction of the electric field of a dipole?

The direction of the electric field of a dipole is perpendicular to the line connecting the two charges, pointing away from the positive charge and towards the negative charge.

4. What happens to the electric field of a dipole as the distance increases?

As the distance from the dipole increases, the strength of the electric field decreases. This is because the inverse square law states that the electric field is inversely proportional to the square of the distance.

5. How does the orientation of a dipole affect the electric field?

The orientation of a dipole can greatly affect the electric field. When the dipole is aligned with the direction of the electric field, the field will be stronger. However, when the dipole is perpendicular to the electric field, the field will be canceled out and there will be no net electric field at that point.

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