Please help with practice problems.

Question 4 : The current i through R1 in the circuit diagram below is 40 mA. a. What is the current through R2, R3, and R4? b. What is the potential difference between A and B? R4 = 411 v1 = 1.5V [/2 R1 =20. Question 5 : As shown in the picture below, a point charge with a charge of q is located on the centerline of a square ABCD with a side length of I. The point charge is located at a distance of |/2 from the square. Find the magnitude of the electric field flux passing through the square