Solve the all parts of given problem:
Problem: Two 10-cm-diameter charged rings face each other, 28cm apart. The left ring is charged to -20nC and the right ring is charged to +20nC.
Part A: What is the magnitude of the electric field E? at the midpoint between the two rings?
Part B: What is the direction of the electric field E? at the midpoint between the two rings?
Part C: What is the magnitude of the force F? on a -1.0 nC charge placed at the midpoint?
Please show me how work it out for above problem.