Final answer:
The magnitude of the electric field at the midpoint between two disks is an average of the fields from each disk if they are along the same line. If the fields are perpendicular, the Pythagorean theorem is used to find the resultant field.
Step-by-step explanation:
The magnitude of the electric field at the midpoint between two disks can be found using the principle of superposition and the Pythagorean theorem if the fields are perpendicular to each other. For parallel plates with uniform charge distribution, the electric field strength is fairly uniform across the gap, barring edge effects. Therefore, at the midpoint between two disks or plates with a specified electric field strength, the magnitude of the electric field would be an average of the fields due to each plate if they are along the same line. However, if the given values of E1 and E2 represent fields from charges or plates positioned at right angles, which seems to be implied by the setup of a right triangle, we would calculate the resultant field using the Pythagorean theorem: Etot = √(E1² + E2²). In the given example, where E1 is exactly twice E2, this calculation would lead to a simple ratio in the resultant field strength.