Question

1. A hollow metal object shaped like a rectangular block is charged by conduction. Which of the following is almost immediately true? a)The charge density is uniform over the entire surface b)The charge density is greater on corners and edges c) The charge density is greatest on the flat areas d) The charge density is zero

2. Describe the difference in shape for equipotential surfaces associated with a single negative charge and those associated with a single positive charge of twice the magnitude. a) There is no difference b)The positive charge equipotentials are not spherical c) The negative charge equipotentials are not spherical.

3. Electrostatic equilibrium is a condition that occurs very rapidly when a conductor takes on excees charge. Which of the following is not true about this condition? a) The condition occurs to to rapid charge migration. b) The E-field at equilibrium is only internal to the conductor. c) The excess charge resides on the surface. d) The electric potential is uniform below the surface

Answer 1

1. The charge density is non uniform because the object is a rectangular metallic block. In principle, the charge density is greater on the corners and edges. Therefore, (b) is correct answer

2. Each of the two will have same equipotential surfaces except the density of surfaces. Therefore, (a) is the correct option.

3. Actually, E-field vanishes inside the conductor, otherwise the charge flow will take place until the equilibrium is established again. Therefore, there is no internal E-field. Hence, (b) is the correct option.