What is the magnitude of the electric field if one charge is positive and the other negative, both of magnitude 5.43 µC?

The field magnitude depends upon the location. What location are you taking about?

Two positive charges of 5.43 µC each are

508 cm apart.
Find the electric field midway between
them.

To find the magnitude of the electric field between two charges, we can use Coulomb's Law. Coulomb's Law states that the magnitude of the electric field between two charges is given by the equation:

E = k * (|Q1| * |Q2|) / r^2

Where:
- E is the magnitude of the electric field.
- k is the electrostatic constant, approximately equal to 9 * 10^9 Nm^2/C^2.
- |Q1| and |Q2| are the magnitudes of the charges.
- r is the distance between the charges.

In this case, we have two charges of magnitude 5.43 µC (microCoulombs) each. Since one charge is positive and the other is negative, we can say that |Q1| = |Q2| = 5.43 µC.

Now, we need to determine the distance between the charges. Unfortunately, the distance (r) is not mentioned in the question. Therefore, we cannot calculate the magnitude of the electric field without knowing the distance between the charges.

If you provide the distance between the charges, I can help you calculate the magnitude of the electric field using Coulomb's Law.