7. A charge QA = -20 pC is located at A(-6, 4, 7), and a charge Q: = 50UC is at B(5, 8,-2) in free space. If distances are given in meters, find: (2) RAE (b) RAE (c) Determine the vector force exerted on QA by Q: if co = 8.854 x 10-12 F/m. 8. A point charge of 10^-9 C is placed at a point A in free space. Calculate the intensity of electrostatic field at a distance 5 cm from point A 9. A charge of -0.3pC is located at A(25,-30, 15) (in cm), and a second charge of 0.5UC is at B(-10, 8, 12) cm. Find E at: (a) the origin (b) P (15, 20, 50) cm. 10. Calculate the total charge within each of the indicated volumes: (a) 0.1 s |x, D/, z) = 0.2: p, = (b) 0 s p = 0.1, 0sQ= 1, 2=z=4; p, = p2?' sin0.60 11. A charge Q. located at the origin in free space produces a field for which E: = 1 KV/m at point P(-2, 1,-1). (a) Find Qo ; (b) . Find E at M(1, 6, 5) in rectangular coordinates; (c) . Find E at M(1, 6, 5) in cylindrical coordinates; (dd) . Find E at M(1, 6, 5) in spherical coordinates. 12. A uniform volume charge density of 0.2 pC/m 3 is present throughout the spherical shell extending from / = 3 cm to r = 5 cm. If pv = 0 elsewhere, find the total charge present throughout the shell. 13. A spherical volume having a 2-um radius contains a uniform volume charge density of 10^15 C/m 3. What total charge is enclosed in the spherical volume? 14. A uniform line charge of 16 nC/m is located along the line defined byy = -2, z = 5. If ? = ?( , find E at P(1, 2, 3). 15. A uniform line charge of 2C/m is located on the z axis. Find E in rectangular coordinates at P(1, 2, 3) if the charge exists from -4 s z = 4