Electricity and Magnetism Flashcards
Formula for the cell potential of an electrochemical cell with known half-reaction standard reduction potentials.
Formula for the electrical potential energy.
U = electrical potential energy in J
k = Coulomb’s constant = 9 x 109 N m2 C-2
q1 = charge of 1st particle in C
q2 = charge of 2nd particle in C
r = distance between particles in m
q = charge of point charge in C
V = electric potential in V
Used to calculate electric potential energy between two charged particles separated by a known distance or to calculate the electric potential energy of a point charge in a position of known electric potential.
Electric Field
Used to calculate electric field strength when either the electric force on a test charge generated by the electric field is known or the magnitude of the source charge and distance from source charge are known
E = electric field strength in N/C
F = electric force in N
q = test charge in C
k = Coulomb’s constant = 9 x 109 N m2 C-2
Q = source charge in C
r = distance from source charge in m
States that the electric field strength at a given position in space equals the electric force it generates on a test charge divided by the magnitude of that source charge. Also, the electric field strength at any position in space is directly proportional to the magnitude of its source charge and inversely proportional to the square of the distance from its source charge.
Coulomb’s Law:
Used to calculate the electric force between point charges or the electric force generated by an electric field on a point charge
F = electric force in N
k = Coulomb’s constant = 9 x 109 N m2 C-2
q1 = charge of 1st particle in C
q2 = charge of 2nd particle in C
r = distance between particles in m
q = charge of a point charge in C
E = electric field strength in N/C
States that the electric force between two point charges is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. Also, the magnitude of electric force on a point charge within an electric field equals the product of its charge and the electric field strength.
Lorentz Force:
Describes the force on a charged particle moving through both an electric field and a magnetic field.
F = force in N
q = charge in C
E = electric field strength in N/C
v = speed of charged particle in m/s
B = magnetic field strength in T
𝜃 = angle between direction of charged particle movement and direction of magnetic field in degrees
Magnetic Force:
Formula for the magnetic force applied by a magnetic field on a moving point charge.
F = force in N
q = charge in C
v = speed of charge in m/s
B = magnetic field strength in T
𝜃 = angle between direction of charged particle movement and direction of magnetic field in degrees
Magnetic Force on Current Carrying Wires:
Formula for the magnetic force applied by a magnetic field on a straight current-carrying wire.
F = force in N
i = current in A
L = length of wire in m
B = magnetic field strength in T
𝜃 = angle between wire and direction of magnetic field in degrees
Volts Root Mean Square
Vrms = effective voltage in V
Vmax = maximum voltage in V
Describes the effective voltage of an AC circuit, defined as the root mean square of the maximum voltage.
Ohm’s Law: Used to determine the characteristics of a circuit.
V = voltage in V
I = current in A
R = resistance in Ω
States that the current through a conductor between two points is directly proportional to the voltage across the two points.
Resistivity: Used to calculate the resistance of a wire or to calculate different characteristics of a wire of known resistance.
R = resistance in Ω
𝜌 = resistivity in Ω m
L = length in m
A = cross sectional area in m2
States that the resistance of a wire is directly proportional to its length and inversely proportional to its cross-sectional area.
Formula for the energy stored in a charged capacitor.
U = stored energy in J
C = capacitance in F
𝛥V = potential difference across a capacitor in V
Describes the effective current of an AC circuit, defined as the root mean square of the maximum current.
Irms = effective current in A
Imax = maximum current in A
Capacitance: Used to calculate charge stored, capacitance, or voltage across a capacitor when the other 2 are known.
Q = magnitude of charge stored in C
C = capacitance in F
𝛥V = potential difference between plates in V
Formula for the charge stored on a capacitor in a circuit.
