Chapter 20

Charging by _____ charges a neutral body by touching it with a charged body; whereas charging by _____ charges an object without touching it with a charged body. a. conduction, induction b. induction, conduction c. force, conduction d. force, induction

a

The distance between two charges q a and q b is r, and the force between them is F. What is the force between them if the distance between them is doubled? a. F/4 b. 4F c. 9F d. F/9

a

Which of the following materials is the best conductor of electricity? a. Wet skin b. Glass c. Dry air d. Rubber

a

_____charges repel, whereas _____ charges attract. a. Like, opposite b. Opposite, like c. Positive, negative d. Negative, positive

a

A/An _____ is a material in which charges will not move easily, whereas a/an _____ is a material that allows charges to move about easily. a. conductor, insulator b. insulator, conductor c. electroscope, conductor d. insulator, electroscope

b

When two bodies are charged, the total charge before and after charging remains the same because of: a. quantization of charges b. conservation of charges c. law of induction d. Coulomb's law

b

Electric forces can be either repulsive or attractive, whereas gravitational force is always: a. neither a nor b b. repulsive c. attractive d. both a and b

c

Which of the following statements is true about electric forces? a. Electric forces cause objects to only attract each other. b. Electric forces cause objects to only repel each other. c. Electric forces cause objects to repel or attract each other. d. Electric forces have no effect on each other

c

When a conducting sphere is charged positively, initially the charge is deposited on the left side. However, due to the sphere's conducting nature, the charge spreads uniformly throughout the surface of the sphere. Charge is uniformly distributed because: a. charged atoms at the location of charge distribute throughout the surface. b. excess protons move from the location of charge to rest. c. excess charge within the sphere moves out into the ground from the surface. d. electrons within the sphere move out toward the excess protons.

d