A 2-wire d.c. ring distributor is 600 m long and is fed with 220 V at point S. A uniformly distributed load of 50 A is tapped from the line every 100 m at points A, B, C, D and E respectively. If the resistance per 100 m of single conductor is 0.03 Ω, find: 

a) The point of minimum potential. 

b) The voltage at each load point. 

c) If points S and B are linked through an interconnector of resistance 0.02 Ω, determine the new voltage at each load point. 

d) What is the new point of minimum potential?