11. At what separation, the two charges of magnitude 10 C be held to produce a dipole moment 5 10-2 C-m? Ans. 5 cm 12. Find the electric field produced due to an electric dipole of moment 2 108 C-m on the axis of dipole 100 cm away from its centre. Consider the separation between the charges is negligible compared to the distance. Ans. 3.6 102 N/C 13. Two equal and opposite charges of magnitude 2 C are placed at a separation of 1 cm. What would be the electric field at the point lies in equatorial plane along the bisector line of the dipole 1 m away from its centre? Ans. 1.8 102 N/C 14. Calculate the torque produced, when an electric dipole with charges 1 C is held at 30, in an electric field of magnitude 102 N/C. The separation between the charges is 2 cm. Ans. 10-6 N-m 15. A point charge produces 5 N/C electric field at a point 40 cm from it. Find the magnitude of the charge. Ans. 8.9 10-11 C