Unit 11 Variables Quiz - Physics C

q

charge: property of an object [C]

n

number of fundamental charges

e

fundamental charge: charge of an electron or proton [1.6 x 10^-19C]

I

current: flow of objects with charge [A or C/s]

V

Electric potential: the energy that a hypothetical coulomb of charge would have at that spot [V or J/C]

ΔV

Electric potential difference: the change in energy that a hypothetical coulomb of charge would undergo between two spots [V or J/C]

ε (EMF)

EMF: ideal potential difference of a battery [V]

R

Resistance [Ω ohm]

l (circuits)

Length of a resistor [m]

A (resistor)

Cross-sectional area of a resistor [m^2]

ρ (rho)

Resistivity: how resistive a material is [Ωohm*m]

σ (sigma)

Conductivity: how conductive a material is (inverse of resistivity) [(Ωm)^-1]

P

Power: rate of change of energy [W or J/s]

|dV/dx|

Electric fields point from high to low potential [V/m]

C

Capacitance [F]

κ

Dielectric constant [Dielectric of air is 1.00]

A (capacitance)

Plate area [m^2]

d (capacitor)

Plate separation [m]

U_C

Energy stored in the electric field of capacitor [J]

v_d

Drift velocity of electrons in a current [m/s]

J

Current density = current/cross-sectional area [A/m^2]

Formulas for the rate of energy dissipation in a resistor or light bulb

P = I^2*R = DeltaV^2/R = I*DeltaV

Three formulas for energy storage in a capacitor

U_C = 1/2QDeltaV = 1/2CDeltaV^2 = Q^2/2C