Three Charges Aligned on a Straight Wire

In summary, the conversation discusses the arrangement of three charges along a straight wire and determining the distance of a charge -1.5q3 from the origin in order to cancel out the electric field at the midpoint of the wire. The equation Etotal = 1/4πεo { E1 + E2- E3 } = 0 is used to find the value of x, with E1, E2, and E3 representing the electric fields from the three charges. The conversation mentions some difficulties and confusion in solving the equation, but ultimately the solution involves finding two possible values for x.
  • #1
Thundies22
1
1
Member advised to use the formatting template for all homework help requests
Three charges are aligned along a straight wire as show.
+C ?<--- -3/2 C --->? -C
+ q1 -3/2 q3 - q2
X----------------------------o-----------------------------X
P(midpoint)
|---------------------------- L-----------------------------2L
x=0 -----> +x

Assume that the +q1 charge is situated at the origin and the -q2 charge is located at distance 2L from the origin. Determine the distance that the -1.5q3 charge is from the origin in order that the total electric field at the midpoint of the wire vanishes.

Of course we have the positive charge (E field radially outward) and negative charge (E field radially inward) both directing in the +ve x direction. So we would expect to see the charge -3/2q3 to the left of P (-x) to cancel the two fields in the +x direction from q1 and q2. We would use Etotal = 1/4πεo { E1 + E2- E3 } = 0 and find the distance x by finding a root. Where E1= q/(0-L)2, E2= q/(2L-L)2, E3=3q/2(x-L)2.

I tried this one a few times just going in loops and don't want to confuse anyone one else. For some reason this question which is a trivial 1D problem is getting me lol. Thanks for your support.
 
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  • #2
Looks like your diagram has been messed up by the formatting. To avoid that, enclose such ASCII drawings in
Code:
 ...
. (Click Reply to see what I wrote.)
Also confused by your charge notation. Do you mean charge q1=-1.5q, etc?
 
  • #3
You already have setup the equation correctly (if i understand correctly your three charges are q,-q and -1.5q).

What prevents you from solving the equation for x? You will find two solutions for x is that what confuses you?
 

What is the concept of "Three Charges Aligned on a Straight Wire"?

The concept of "Three Charges Aligned on a Straight Wire" refers to a scenario in which three electric charges are placed in a straight line, with equal distances between them. This scenario is commonly used in physics experiments to study the behavior of electric charges and their interactions with each other.

What is the mathematical equation that represents this scenario?

The mathematical equation that represents this scenario is known as the "Coulomb's Law". It states that the force between two point charges is directly proportional to the product of their magnitudes and inversely proportional to the square of the distance between them. In the case of three charges aligned on a straight wire, the equation can be represented as F = k(q1q2 + q2q3 + q1q3)/d^2, where F is the force, k is the proportionality constant, q1, q2, q3 are the charges, and d is the distance between them.

What is the direction of the force between the three charges?

The direction of the force between the three charges depends on their relative positions. If the middle charge is positive, it will repel the other two charges, and they will experience a force in the opposite direction. If the middle charge is negative, it will attract the other two charges, and they will experience a force in the same direction. The direction of the force can be calculated using vector addition.

How does the distance between the charges affect the force?

The distance between the charges has an inverse relationship with the force. As the distance increases, the force between the charges decreases, and vice versa. This is because the electric field strength decreases with distance, resulting in a weaker force between the charges.

What are some real-world applications of this scenario?

One real-world application of this scenario is in the design of electrical circuits. By understanding the behavior of charges in a straight line, engineers can design circuits with the desired flow of current. This scenario is also used in the study of atomic and molecular structures, as well as in the development of technologies such as particle accelerators and ion thrusters.

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