1. Explain what is meant by the term “a neutral atom.’’Explain what “a negatively charged
atom’’ means.
2. A charged comb often attracts small bits of dry paper that then fly away when they touch the
comb. Explain.
3. Sparks are often seen or heard on a dry day when fabrics are removed from a clothes dryer in
dim light. Explain.
4. Hospital personnel must wear special conducting shoes while working around oxygen in an
operating room. Why?
Contrast with what might happen if people wore rubbersoled shoes.
5. Explain from an atomic viewpoint why charge is usually transferred by electrons.
6. A light, uncharged metallic sphere suspended from a thread is attracted to a charged rubber
rod. After it touches the rod, the sphere is repelled by the rod. Explain.
7. A foreign student who grew up in a tropical country but is studying in the United States may
have had no experience with static electricity sparks or shocks until he or she first experiences an
American winter. Explain.
8. Explain the similarities and differences between Newton’s law of universal gravitation and
Coulomb’s law.
9. A balloon is negatively charged by rubbing and then clings to a wall. Does this mean that the
wall is positively charged? Why does the balloon eventually fall?
10. A light strip of aluminum foil is draped over a horizontal wooden pencil. When a rod
carrying a positive charge is brought close to the foil, the two parts of the foil stand apart. Why?
What kind of charge is on the foil?
11. When defining the electric field, why is it necessary to specify that the magnitude of the test
charge be very small?
12. How could you experimentally distinguish an electric field from a gravitational field?
13. A large metallic sphere insulated from ground is charged with an electrostatic generator
while a student standing on an insulating stool holds the sphere. Why is it safe to do this? Why
would it not be safe for another person to touch the sphere after it had been charged?
PROBLEMS
