AP Physics 2: Electrical Potential and Charge Notes

Vocabulary practice flashcards covering Coulomb's law, charging methods, material properties, and scientific notation review based on lecture notes.

Raising a Power to a Power

Mathematically, if a number and its exponent is raised by another exponent, you multiply the exponents, such as $(5^2)^3 = 5^6$.

Multiplying Scientific Notation

To multiply two numbers in scientific notation, multiply their coefficients and add their exponents.

Dividing Scientific Notation

To divide two numbers in scientific notation, divide their coefficients and subtract their exponents.

Coulomb's Law (1785)

The formula for electrical force expressed as $F = k \frac{q_1 q_2}{r^2}$.

Coulomb Constant (k)

The proportionality constant in Coulomb's Law, equal to $8.9875 \times 10^9\,N \cdot m^2/C^2$; typically approximated as $9 \times 10^9$ for calculations.

Coulomb (C)

The unit for measuring the quantity of charge, where $1\,coulomb = \text{charge of } 6.25 \times 10^{18}\,e^-$.

Elementary Charge Magnitude

The charge of a single electron ($e^-$) or proton ($p$), equal to $1.602 \times 10^{-19}\,C$.

Electron Volt (eV)

A unit of energy defined by the relation $1\,eV = 1.602 \times 10^{-19}\,J$.

Charge Quantization

The principle that an object cannot have a charge smaller than that of a single electron.

Conductors

Materials with a loose hold on their outermost (valence) electrons, allowing for the movement of electricity; examples include metals and salt water.

Insulators

Materials with a strong hold on their outermost (valence) electrons, preventing the easy flow of electricity; examples include rubber, glass, and plastic.

Vacuum and Distilled Water

Special cases of insulators because they contain no electrons (vacuum) or no loose ions and electrons (distilled water).

Semiconductors

Materials like silicon that can switch from being a good conductor to a good insulator by changing a very small number of atoms; used as switches in computer chips.

Superconductivity

The ability of a material to flow a near infinite amount of current at extremely low temperatures, near absolute zero to $100\,K$.

Charging by Friction

A method of charging that involves knocking outermost (valence) electrons off from materials by rubbing them together, such as a balloon rubbed on hair.

Charging by Contact

A method of charging where physical contact between objects allows electrons to move toward better conductors or larger objects to spread out.

Charging by Induction

When a charged object is brought near an uncharged object and its electrical field induces a charge in the uncharged object without physical contact.

Charge Polarization

The process where the interaction of an electrical field causes electrons to move to one side of an object, creating positive and negative poles.

Electrical Field (E)

A field produced by a build-up of charge, with strength determined by the formula $E = \frac{F}{q}$ and measured in $Newtons/Coulombs$.

Lightning

An atmospheric phenomenon involving charging by friction (ice crystals rubbing) and induction, resulting in a strike when a negative leader from a cloud connects with a positive leader from the ground.