According to Coulomb's Law, the following is true.     a.     The magnitude of the electrostatic force between two charges is directly proportional to the product of the two charges.     b.     The magnitude of the electrostatic force between two charges is inversely proportional to the distance between the charges.     c.     The direction of the electrostatic force between the two charges depends on the sign of the charges.     d.     All of the above.     e.     Only a and c.

Question: Answer the following question about electric charge/field: a. The static electric field INSIDE an object made from a conducting material is a. zero everywhere. b. constant, but not necessarily zero. c. greater than the electric field just outside the object. perpendicular to the surface of the object. d. unaffected by the presence of the conductor.   b. Knowing this, the Electric charges of opposite sign will a. attract each other. b. exert no force on each other. c. repel each other. d. repel and attract each other. e. either repel or attract each other depending on the magnitudes of the charges.

two charges attract each other with a force of magnitude 1.0x10^-5 N. When they are move 4mm apart, the force between them becomes 2.5x10^-6N. The original separation of the two charges was a. 8mm b. 2mm c. 6mm d. 10mm e. 4mm