Electric Field
What is the unit for E Field?
N/C
What is electric potential?
The amount of potential energy per unit charge at a location
What is Flux?
The amount of e-field lines through an area.
What does the letter kappa represent? What is the value of kappa in a vacuum?
the ratio of ε for a dielectric to ε0. In a vacuum, kappa is 1 because ε0/ε0 = 1.
Magnetic field lines exit the _____ pole and reenter at the _____ pole.
North; South
What is the unit for electric charge?
Coulombs
What is the unit for electric potential?
Volts or Joules/Coulomb
What is the unit for flux?
N/C m2
What are the units for capacitance and resistance?
Farads and Ohms
What is the unit for Magnetic field?
Tesla (Like the Car :O !!!1!!!1)
…or the Gauss :/
What is Coulomb's law?
F = k (q1 * q2)/(r^2)
What is an equipotential surface?
A surface with the same electric potential throughout
what is Gauss' law?
Φ = Qenclosed/ε0
What is the EMF of an ideal battery equal to?
The voltage of the battery
Magnetic force on a moving charge is equal to what? What about on a wire?
F = qv X B
F = IL X B
Using Coulomb's law, derive the equation for E Field.
F = qE
F = k (Qq)/(r^2)
k (Qq)/(r^2) = qE
E = kQ/(r^2)
How do you find the point at which the electric field is the greatest given equipotential lines?
The field is greatest where the lines are closest
Sometimes when working with gauss' law it is necessary to use charge densities. What are the 3 different types of charge densities and their symbols?
λ - linear density (c/m)
σ - area density (c/m2)
ρ - volume density (c/m3)
What is the relationship between resistance and resistivity?
R = (ρℓ)/A
A proton moving horizontally to the right encounters a magnetic field going vertically down. Which direction is the magnetic force in?
"into the page"
What is the Electric field 10 meters directly to the right of a -10 coulomb charge?
E = kQ/(r^2)
E = k(-10)/(10^2)
E = -10k/100 = -k/10
-k/10 N/C left
Which direction do e field lines go relative to equipotential lines?
Perpendicular and towards lower potential
How do you find the e-field within an insulated sphere of uniform charge Q?
Φ = EA = 4Eπr2= qenc/ε0
ρ = Q/V = qenc/v
Q/((4πR3)/3) = qenc/((4πr3)/3)
Q/R3 = qenc/r3
qenc = (Qr3)/R3
4Eπr2 = (Qr3)/(ε0R3)
E = (Qr)/(4πε0R3)
E = (kQr/R3)
How do you find the equivalent capacitance for capacitors in series and parallel?
Capacitors in parallel: Cp = ∑Ci
Capacitors in series: 1/Cs = ∑1/Ci
The magnetic force on a wire of any shape is _______ the force on a straight wire connecting the two endpoints of the shape. (Greater than, less than, equal to)
equal to