A square insulating sheet 80.0 cm on a side is held horizontally. The sheet has 7.50 nC of charge spread uniformly over its area. Required:
a. Calculate the electric field at a point 0.100 mm above the center of the sheet.
b. Estimate the electric field at a point 100 m above the center of the sheet.
c. Would the answers to parts (a) and (b) be different if the sheet were made of a conducting material? Why or why not?

Which of the following is part of the explanation or description of electromagnetic waves? (select all that apply) a. electrically charged molecules in a medium transfer their energy to nearby electrically charged molecules. b. a changing electric field causes a changing magnetic field. c. magnetic molecules in a medium transfer their energy to nearby magnetic molecules. d. a changing magnetic field causes a changing electric field.