The structure of the NH, molecule is approximately that of an equilateral tetrahedron, with three H ions forming the base and an N_ion at the apex of the tetrahedron. The length of each side is 1.64 X 10-10 m. Calculate the electric force that acts on each ion. THE ELECTRIC FIELD 37 A point charge of 40 aC is at the origin. What are the magnitude and direction of the electric field on the r axis at (@) r - 6.0 m and (b) x - -10 m? (c) Sketch the function _ versus x for both positive and negative values of . (Remember that E is negative when E points in the -x direction.) ssM 38 . Two point charges, each +4.0 /C, are on the r axis; one point charge is at the origin and the other is at x - 8.0 m. Find the electric field on the x axis at (() x = -2.0m, (b) x = 20m, (c) x = 6.0 m, and (d) x - 10 m. (8) At what point 2app (A Cketch E versus a for