Four charge points with dimensions of; Q1(-10,0,10), Q2 (10,0,10), Q3(10,0,-10) and Q4 (-10,0,-10) in Cartesian system are surrounded with air. Q1=-Q4=5muC.
a. If Q2= Q3=0, find Vectors E and D.
b. For Q2= -Q3 5 μC forces applied to each point from other charges.