Net Electric Field Between Two Point Charges

AI Thread Summary
The discussion focuses on calculating the net electric field E between two point charges, q1 and q2, separated by a distance of 0.10 m. The user attempts to compute E(-0.100) using the electric field equations but receives an incorrect result. Confusion arises regarding the placement of charges and the signs in the calculations, particularly the negative value for the distance and the exponent used for q2. The thread highlights the importance of correctly applying the equations and checking for potential errors in calculations or assumptions about coordinate placement. Clarifying these points is essential for arriving at the correct solution.
Rachelbot12

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.
 
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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 ?
 
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