24. Electric Force & Field; Gauss' Law

A plastic rod that has been charged to −15 nC touches a metal sphere. Afterward, the rod's charge is −10 nC. How many charged particles were transferred?

A plastic rod that has been charged to −15 nC touches a metal sphere. Afterward, the rod's charge is −10 nC. What kind of charged particle was transferred between the rod and the sphere, and in which direction? That is, did it move from the rod to the sphere or from the sphere to the rod?

Figure 22.8 showed how an electroscope becomes negatively charged. The leaves will also repel each other if you touch the electroscope with a positively charged glass rod. Use a series of charge diagrams to explain what happens and why the leaves repel each other.

(II) When an object such as a plastic comb is charged by rubbing it with a cloth, the net charge is typically a few microcoulombs. If that charge is 2.4 μC, by what percentage does the mass of a 9.0-g comb change during charging?

(II) A person scuffing her feet on a wool rug on a dry day accumulates a net charge of -34 μC. How many excess electrons does she get, and by how much does her mass increase?