Net Electric Field Between Two Point Charges

• Rachelbot12
In summary, the task was to calculate the net electric field E(x) as a function of x for two point charges separated by a distance d. The equations used were E(x<0)= -k [(Q1/x^2)+(Q2/(d-x)^2)], E(0<x<d)= k [(Q1/x^2)-(Q2/(d-x)^2)], and E(d<x)= k [(Q1/x^2)+(Q2/(d-x)^2)]. When attempting to calculate E(-0.100), the result was -1.1e7 N/C, which was marked incorrect due to potential typing/calculator errors including the origin of the x-coordinate and incorrect values for the charges.

Homework Statement

Two point charges q1 = 4.90×10-5 C and q2 = 2.45×10-4 C are separated by a distance d = 0.10 m. Compute their net electric field E (x) as a function of x for the following positive and negative values of x, taking E to be positive when the vector E points to the right and negative when E points to the left.What is E(-0.100)?

Homework Equations

I tried the following equations, but I couldn't get any to work for any of the values of x:
E(x<0)= -k [(Q1/x^2)+(Q2/(d-x)^2]
E(0<x<d)= k [(Q1/x^2)-(Q2/(d-x)^2]
E(d<x)= k [(Q1/x^2)+(Q2/(d-x)^2]

The Attempt at a Solution

E(-0.100)= -9e9 [(4.90e-5/-0.01)+(2.45e4/0.04)] = -1.1e7 N/C

This is being marked incorrect and I don't know what I'm doing wrong. I've attempted multiple times with no luck.

Does the exercise mention the origin of the x-coordinate ? Your equations place Q1 at x = 0 at Q2 at x = d.

I expect that is OK. But then I don't understand the minus sign before the 0.01
and I also don't understand the 2.45e4 if the charge is 2.45e-4 Coulomb !?

One or more typing / calculator keying errors ?

What is the net electric field between two point charges?

The net electric field between two point charges is the resultant electric field at a point due to the influence of both charges. It is the vector sum of the electric fields produced by each individual charge.

How do you calculate the net electric field between two point charges?

The net electric field can be calculated using the formula E = kQ/r^2, where E is the net electric field, k is the Coulomb constant, Q is the magnitude of the charge, and r is the distance between the two charges. The direction of the net electric field can be determined using the principle of superposition, where the direction of the field is the same as the direction of the resultant force on a positive test charge placed at that point.

What is the relationship between the distance between two point charges and the net electric field?

The net electric field between two point charges is inversely proportional to the square of the distance between them. This means that as the distance between the charges increases, the strength of the net electric field decreases. This relationship is described by the inverse square law.

How does the direction of the charges affect the net electric field between them?

The direction of the charges affects the direction of the net electric field. If the two charges have the same sign (both positive or both negative), the net electric field will be in the same direction as the individual electric fields. If the two charges have opposite signs, the net electric field will be in the direction of the stronger charge.

Can the net electric field between two point charges be negative?

Yes, the net electric field can be negative. This occurs when the two charges have opposite signs and the net electric field is directed towards the weaker charge. In this case, the magnitude of the net electric field will still be positive, but the direction will be negative.