III. Read each item carefully.Encircle the letter of the best answer. (3 points each number)

1. When a rubber rod is rubbed with cloth, the rod becomes negatively charged. Why?

a. The cloth gains protons.

b.The cloth loses electrons.

c. The rod gains protons.

d. The rod loses electrons.

2. M, N, O,and Pare pith balls which behave as follows: M repels N; M attracts O;and O repels P. If P is positively charged.

a. N must be positively charged.

b) N must be neutral.

C. N must be negatively charged.

d. N may be positively charged or neutral.

3. After triboelectric charging, which of the following ends up negatively charged?

a. silk

b. glass

c. aluminum

d.)rubber balloon .

4. What would be the net charge of human hair if it were rubbed with plastic?

a positive

b. negative

с. Zero

d. none of the above​