Final answer:
To determine the electric field at the -5.0 nC charge, use the equation E = kQ/r², considering the contributions from all nearby charges. The direction of the field is away from the negative charge location.
Step-by-step explanation:
To find the electric field at the location of the -5.0 nC charge, we use the formula E = kQ/r², where k is Coulomb's constant (approximated as 8.99 x 10⁹ Nm²/C²), Q is the charge causing the field, and r is the distance from the charge to the point where the field is being calculated.
The direction of the electric field is always away from positive charges and towards negative charges. Since the question specifies finding the magnitude and direction at the location of a negative charge, we know that the direction of the field at this point will be away from the -5.0 nC charge. If there are other charges nearby, each one will contribute to the total electric field at that point based on its sign and magnitude.