15. calculate the electric field intensity in mill volts per meter at 30 kw from a 5 km source. a. 189.74 mvm b. 456.20 mvm c. 14.21 mvm d. 158.0 mvm 16. what is the index of refraction of a certain substance if a light travel through the substance at 100 meters at a time is to 140 meters to air a. 2.2 b. 1.4 c. 15.2 d. 48.2 17.