Chapter 6 - Static Electricity

A plastic comb attracts small bits of paper. One possible explanation is that _________.

• The comb is negatively charged and the paper is positively charged.

• Both the comb and the paper are positively charged.

• Both the comb and the paper are negatively charged.

• Both the comb and the paper have mixtures of negative and positive charges.

An electroscope has an excess of 3.9 × 10⁸ electrons. What is the charge on the electroscope?

• 1.6 × 10^–11 C

• 2.4 × 10^–11 C

• 4.1 × 10^–11 C

• 6.2 × 10^–11 C

Which is a correct statement about how objects are charged?

• Objects are almost always charged by creating or destroying protons.

• Objects are almost always charged by transferring protons from one object to another.

• Objects are almost always charged by transferring electrons from one object to another.

• Objects are almost always charged by creating or destroying electrons.

If a positive rod is brought near the knob of a neutral electroscope, but does not touch it, what will occur?

• The knob will become negatively charged, and the leaves will repel each other.

• The knob will become negatively charged, and the leaves will remain closed.

• The knob will become positively charged, and the leaves will repel each other.

• The knob will become positively charged, and the leaves will remain closed.

A lightning bolt transfers a charge of 17 C. How many elementary electrical charges does the lightning bolt transfer if it strikes the ground?

• 1.1 × 10¹⁸ electrons

• 2.7 × 10¹⁸ electrons

• 1.1 × 10²⁰ electrons

• 2.7 × 10²⁰ electrons

Which of the following completely summarizes Coulomb's results?

• 
• 
• 
• 

A charge, q_A, experiences an attractive force of 1.5 × 10² N as a result of a charge, q_B, located 2.4 cm away. If q_B has a charge of +5.2 × 10^–6 C, what is the charge of q_A?

• –1.3 × 10^–6 C

• –1.8 × 10^–6 C

• –3.1 × 10^–6 C

• –7.7 × 10^–6 C

How will the force between two charged spheres be changed if the distance between the spheres' centers is reduced to half its original value?

• multiplied by 2

• multiplied by 4

• divided by 2

• divided by 4

The diagram shows three charged spheres. Sphere A has a charge of 2.0 × 10^–6 C, sphere B has a charge of 3.0 × 10^–6 C, and sphere C has a charge of 4.0 × 10^–6 C. What is the magnitude of the net force on sphere A? (r_AB = 2.0 × 10^–2 m and r_AC = 2.0 × 10^–2 m)

• 1.4 × 10² N

• 1.6 × 10² N

• 2.0 × 10² N

• 2.3 × 10² N

An electroscope is negatively charged, with the leaf at an angle of about 45°. An insulating rod is slowly brought to (but not touching) the knob of the electroscope and the leaf falls. This suggests that the rod is ___________.

• uncharged or positively charged

• uncharged or negatively charged

• positively charged

• negatively charged