Physics Q4 Test II

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 repel or attract each other.

• c. Electric forces have no effect on each other.

• d. Electric forces cause objects to only repel each other.

Which of the following materials is the best conductor of electricity?

• a. Rubber

• b. Dry air

• c. Glass

• d. Wet skin

When two bodies are charged, the total charge before and after charging remains the same because of:

• a. conservation of charges

• b. quantization of charges

• c. Coulomb’s law

• d. law of induction

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. excess electrons within the sphere move toward excess protons.

• b. excess protons move from the location of charge to rest.

• c. charged atoms at the location of charge distribute throughout the surface.

• d. excess charge within the sphere moves out into the ground from the surface.

The distance between two charges and 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

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. force, conduction

• b. induction, conduction

• c. force, induction

• d. conduction, induction

Electric forces can be either repulsive or attractive, whereas gravitational force is always:

• a. attractive

• b. repulsive

• c. both a and b

• d. neither a nor b

_____charges repel, whereas _____ charges attract.

• a. Negative, positive

• b. Like, opposite

• c. Positive, negative

• d. Opposite, like

Metals contain _____ electrons; rubber has _____ electrons.

• a. insufficient, excess

• b. free, bound

• c. bound, free

• d. excess, insufficient