Glossary
Conductors
Materials that allow electric charge to move freely through them due to the presence of many free electrons.
Example:
Metals like copper are excellent conductors and are used in electrical wiring because electrons can easily flow through them.
Coulomb's Law
A fundamental law stating that the electrostatic force between two point charges is directly proportional to the product of their magnitudes and inversely proportional to the square of the distance between them.
Example:
Using Coulomb's Law, you can calculate the exact attractive force between an electron and a proton in a hydrogen atom.
Electric Force
The fundamental force that governs how charged objects interact, resulting in either attraction or repulsion.
Example:
When you rub a balloon on your hair, the electric force causes your hair to stand on end as it's attracted to the balloon.
Electric Permittivity (ε)
A measure of how easily a material becomes polarized in an electric field, indicating its ability to store electrical energy or transmit an electric field.
Example:
Materials with high electric permittivity are often used in capacitors to increase their charge storage capacity.
Electrostatic Forces
Forces between stationary electric charges. Unlike gravity, they can be both attractive and repulsive and are significantly stronger at atomic scales.
Example:
The reason your hand doesn't pass through a table is due to the strong electrostatic forces between the atoms in your hand and the table.
Free Space Permittivity (ε₀)
A fundamental physical constant representing the electric permittivity of a vacuum, serving as a baseline for how electric fields behave in the absence of matter.
Example:
The constant free space permittivity is a crucial component in Coulomb's Law, determining the strength of electric force in a vacuum.
Gravitational Forces
The attractive force between any two objects with mass. It is much weaker than electric forces at small scales but dominates at large scales due to the electrical neutrality of most large objects.
Example:
The gravitational forces between the Earth and the Moon keep the Moon in orbit.
Insulators
Materials that resist the flow of electric charge because their electrons are tightly bound and cannot move freely.
Example:
Rubber gloves act as insulators, protecting electricians from electric shock by preventing current from flowing through their bodies.
Like Charges Repel
A principle stating that objects carrying the same type of electric charge (both positive or both negative) will exert a repulsive force on each other, pushing them apart.
Example:
If you bring two positively charged pith balls close together, they will visibly push away from each other because like charges repel.
Opposite Charges Attract
A principle stating that objects carrying different types of electric charge (one positive and one negative) will exert an attractive force on each other, pulling them closer.
Example:
The reason a charged comb can pick up small pieces of paper is that the paper becomes polarized, and the opposite charges attract.
Polarization
The process where an electric field causes a rearrangement of charges within a material, creating a separation of positive and negative charge centers.
Example:
When a charged rod is brought near a neutral insulator, the atoms within the insulator undergo polarization, aligning their charge distributions.