PY 131 Chapter 22: Electrostatics

What is electrostatics?

Phenomena associated with electricity and magnetism.

What are some examples of electrostatic phenomena in nature?

Lightning, catfish/electric eels, lodestones, and St Elmo’s fire.

How did the connection between electricity and magnetism come to be recognized?

It was first realized that there were two different phenomena - electricity and magnetism - and then later the connection between them was found.

What are electrics?

Materials that acquire the ability to influence other objects when rubbed.

What is the proper name for generating an electric charge by rubbing?

The triboelectric effect.

What are positive and negative charges?

Positive and negative charges are two kinds of charges that were discovered by Benjamin Franklin.

What happens when positively charged materials are brought close to other positively charged materials?

They repel each other.

What happens when negatively charged materials are brought close to other negatively charged materials?

They repel each other.

What happens when negatively charged materials are brought close to positively charged materials?

They attract each other.

What is the source of charge on electric materials?

Electrons.

What is the charge of electrons?

Electrons have negative charge.

What is the charge of protons?

Protons have positive charge.

What is the charge of neutrons?

Neutrons have no charge.

What is the smallest possible charge anything can have?

±e/3, where e is the charge of an electron.

What is the SI unit of charge?

The coulomb.

How is the force between electric charges related to the force due to gravity?

The size of the force is inversely proportional to the square of the distance between the charged materials and proportional to the product of the charges of the two objects, just like the force due to gravity.

What is Coulomb's Law?

The force between two charges is given by F=k(q1q2/d^2), where F is the force, q1 and q2 are the charges, d is the distance between the charges, and k is the constant of proportionality.

What is the constant of proportionality in Coulomb's Law?

k = 9 x 10^9 N m^2/C^2.

What are conductors?

Materials that allow electrons to flow easily through them.

What are insulators?

Materials that do not allow electrons to flow easily through them.