18.2 Conductors and Insulators

What will be the net charge on the sphere?

1. positive
2. negative
3. zero
4. It can be positive or negative depending on the material.

If the balloon is moved away after grounding, what will be the net charge on the sphere?

1. positive
2. negative
3. zero
4. It can be positive or negative depending on the material.

Suppose a speck of dust in an electrostatic precipitator has $1 . \text{0000} \times \text{10}^{\text{12}}$ protons in it and has a net charge of –5.00 nC (a very large charge for a small speck). How many electrons does it have?

A 50.0 g ball of copper has a net charge of $2.00 \mu \text{C}$. What fraction of the copper’s electrons has been removed? (Each copper atom has 29 protons, and copper has an atomic mass of 63.5.)

How many coulombs of positive charge are there in 4.00 kg of plutonium, given its atomic mass is 244 and that each plutonium atom has 94 protons?