You are working as an intern for a meteorological laboratory. you are out in the field taking measurements with a device that measures electric fields. you measure the electric field in the air immediately above the earth's surface to be 119 n/c directed downward. (assume the radius of the earth is 6.37 ✕ 106 m.) (a) determine the surface charge density (in c/m2) on the ground. (b) imagine the surface charge density is uniform over the planet. determine the charge (in c) of the whole surface of the earth. (c) determine the earth's electric potential (in v) due to the charge found in (b). (d) determine the difference in potential (in v) between the head and the feet of a person 1.50 m tall. (ignore any charges in the atmosphere.) v