Solve the all parts of following problem:
Problem: Two 10-cm-diameter charged rings face each other, 20cm apart. The left ring is charged to -22nC and the right ring is charged to +22nC.
Part A: What is the magnitude of the electric field E at the midpoint between the two rings?
Part B: What is the magnitude of the force F on a -1.0 nC charge placed at the midpoint?
Please show solution step by step with details.