Physics Principle and Problems

Paul W. Zitzewitz, Todd George Elliott, David G. Haase

Chapter 20

Static Electricity - all with Video Answers

Educators

Section 1

Electric Charge

Problem 1

After a comb is rubbed on a wool sweater, it is able to pick up small pieces of paper. Why does the comb lose that ability after a few minutes?

Robert Zaballa

Robert Zaballa

Numerade Educator

Problem 2

In the experiments described earlier in this section, how could you find out which strip of tape, $\mathrm{B}$ or $\mathrm{T}$, is positively charged?

Robert Zaballa

Numerade Educator

Problem 3

A pith ball is a small sphere made of a light material, such as plastic foam, often coated with a layer of graphite or aluminum paint. How could you determine whether a pith ball that is suspended from an insulating thread is neutral, is charged positively, or is charged negatively?

Robert Zaballa

Numerade Educator

Problem 4

A rubber rod can be charged negatively when it is rubbed with wool. What happens to the charge of the wool? Why?

Robert Zaballa

Numerade Educator

Problem 5

An apple contains trillions of charged particles. Why don't two apples repel each other when they are brought together?

Robert Zaballa

Numerade Educator

Problem 6

Suppose you hang a long metal rod from silk threads so that the rod is isolated. You then touch a charged glass rod to one end of the metal rod. Describe the charges on the metal rod.

Robert Zaballa

Numerade Educator

Problem 7

You can charge a rubber rod negatively by rubbing it with wool. What happens when you rub a copper rod with wool?

Robert Zaballa

Numerade Educator

Problem 8

It once was proposed that electric charge is a type of fluid that flows from objects with an excess of the fluid to objects with a deficit. Why is the current two-charge model better than the single-fluid model?

Robert Zaballa

Numerade Educator