Solve the all parts of given question:
Question: A square insulating sheet 90.0cm on a side is held horizontally. The sheet has 6.15nC of charge spread uniformly over its area.
Part A: Calculate the electric field at a point 0.400mm above the center of the sheet.
Part B: Estimate the electric field at a point located a distance 135m above the center of the sheet.
Having trouble with this physics question, can you please explain with the answer.