Optional course of physics high school 3- 1

1. A: In the dry and manic season, when the coat is taken off, the coat and the body are charged with the same amount but different numbers due to friction. Then, when you touch the metal door handle with your hand, your body will discharge and you will feel an electric shock. 2. A part of conductor B is freely attracted by the positive charge of A and accumulates at the left end of B, and the right end will be positively charged due to the loss of electrons. The attraction of A to the left end of B is greater than the repulsion to the right end, and there is attraction between A and B. 3. Answer: According to Coulomb's discovery, after two identical charged metal balls contact, the amount of charge is the same. So let ball A and ball B contact first, and then ball B has a charge of Q/2. Then let ball B contact ball C, and ball B and ball C will be charged with Q/4 respectively; Finally, ball B touches ball A again, and ball B is charged (q/2+q/4)/2=3q/8. 4. Answer: According to Coulomb's law, the charge of atomic nucleus is the charge of meta-charge. 5. Let the charges of balls A and B be q and -q respectively, and the distance is r, then f =-kq 2/r 2. When c touches a, the charge of a becomes Q/2. The charge of c is also Q/2. After C touches A, the charge of B becomes (-q+q/2)/2 =-q/4; At this time, the electrostatic force between a and b becomes: F/8 is obtained according to Coulomb's law. In this case, if the distance between A and B is doubled, the electrostatic force between them becomes F/32.6. 7.& lt/SPAN>。 & lt/SPAN>。 & lt/SPAN>。