Question 1

Which of the following best describes a conductor?

Accepted Answer

A material through or along which charges easily move.

Question 2

When a charged rod touches the metal sphere at the end of a conducting rod connected to an electroscope, what happens?

Accepted Answer

Charge flows from the sphere to the vane, causing the vane to rotate away from vertical.

Question 3

Which statement is true about the charge of a proton and an electron?

Accepted Answer

They have equal magnitude but opposite sign, $$|q_p| = |q_e| = e.$$

Question 4

If an atom has more electrons than protons, what is it called?

Accepted Answer

A negative ion

Question 5

Which of the following is a consequence of the law of conservation of charge?

Accepted Answer

Charge can be transferred but the total charge remains constant.

Question 6

Quarks have fractional charges. What is the charge of an up quark?

Accepted Answer

$$+\frac{2}{3}e$$

Question 7

A proton consists of two up quarks and one down quark. What is its total charge?

Accepted Answer

$$+e$$

Question 8

Why are metals good conductors?

Accepted Answer

Their outer atomic electrons become detached and move freely throughout the solid.

Question 9

What happens when you briefly touch a positively charged electroscope disk with your finger?

Accepted Answer

The excess charge on the electroscope decreases and the excess charge on you increases.

Question 10

What is grounding?

Accepted Answer

Connecting an object to the earth to allow charge to flow and neutralize excess charge.

Question 11

What is polarization?

Accepted Answer

A slight separation of positive and negative charges within an object.

Question 12

A negatively charged rod is brought close to the disk of an electroscope (without touching). The vane moves. What is the net charge on the system of disk, post, and vane?

Accepted Answer

$$0$$

Question 13

When a negatively charged rod is brought near a metal rod with zero net charge, what happens due to polarization?

Accepted Answer

An excess of positive charge appears close to the negatively charged rod, and negative charge appears far from it.

Question 14

Why does a wooden (insulating) rod become attracted to a charged rod brought near it?

Accepted Answer

Atoms within the wood polarize, causing a separation of charge that attracts the rod.

Question 15

If a negatively charged rod is brought near packing peanuts, why are the peanuts attracted to the rod?

Accepted Answer

Polarization occurs in the peanuts, causing opposite charges to be closer to the rod.

Question 16

Which of the following statements about ionic solutions is correct?

Accepted Answer

Ionic solutions, such as salt water, are good conductors because ions can move freely.

Question 17

A neutron consists of one up quark and two down quarks. What is its total charge?

Accepted Answer

$$0$$

Question 18

Which process can create ions on the surface of an insulator?

Accepted Answer

Rubbing the insulator, which leaves patches of molecular ions on the surface.

Question 19

If a positively charged electroscope is touched by a neutral person, what happens to the charge on the electroscope and the person?

Accepted Answer

The electroscope loses positive charge and the person gains positive charge.

Question 20

Which of the following is true about the movement of electrons in a conductor compared to an insulator?

Accepted Answer

Electrons in a conductor are free to move throughout the material, while in an insulator they are tightly bound to nuclei.

Electric Charge, Conductors, Insulators, and Polarization: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard