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68 Cards in this Set
 Front
 Back
What are the two forms of Coulomb's Law?

F= ke*qs*qf*r hat/r^2
F=ke*qs*qf*r vector/r^3 

What is the relationship between potential energy and force?

U(x) = ∫ Fdx
F = dU/dx 

What is the equation for the potential energy of two point charges?

U(r)=ke*qs*qf/r


What changes occur to an object as it approaches the speed of light?

length contracts, mass increases, time slows down


What is the equation of a stub?

s=rh hat X l


What is the stub force proportional to?

the charge of the field particle, the thread density, and betaXs


What is the Lorentz force equation?

F=qfEs+qfvf X Bs


What are the equations for electric potential?

V=U/q
V(x) = ∫ Edx 

How can you tell the direction of a field by it's field lines?

The direction is tangent to the line at a given point.


What are two ways of estimating the strength of a field?

Number of lines thru contour/area
number of contours thru line/length 

What is the change in kinetic energy of a particle in an electric field?

DeltaK = qDeltaV


What is the general motion of a charged particle in a uniform magnetic field?

a helical path


What is the equation for the cyclotron radius?

p=qBr


What two equations do we need to know to derive the cyclotron radius equation?

F=mv^2/r
F=qvB 

What is the equation for a mass spectrometer radius?

(1/B)*(sqrt(2mDeltaV/q))


What is the general equation for current?

I=Delta q/Delta t


Relate an electron's circuit voltage to its potential energy?

U=qV


What are the three equations that have to do with resistors?

V=IR
P=IV R=rho l/A 

What is the potential energy of the earth?

0V


What is the charge on an object with respect to charge density?

q= ∫rho dV


What is dA for a square?

dA=L dx


What is dA for a disk?

dA=2 pi r dr


What is dV for a cylinder?

cut in little cylinders: dV=2 pi r L dr
cut into disks: dV=pi r^2 dz 

What is dV for a sphere?

dV=4 pi r^2 dr


What is Gauss's Lavv of Electricity?

EA = 1/epsilon ∫rho dV


How many junction equation are there in a circuit?

One less than the number of junctions.


How many loop equations do you need to analyze a circuit?

# loop eq.=# currents#junction eq.


What is the magnetic field of a long, currentcarrying wire?

B= (mu0 i )/(2pi r)


What is the equation for charge and capacitance?

Q = CV


What is the equation for the electric field inside a capacitor?

E=V/d


What is the geneeral equation for capacitance?

C=epsilon0*A/d


What is the eq. for the energy stored in a capacitor?

U=.5*C*V^2


What is the equation for an RC time constant?

tao = RC


What is the eq. for Q in RC charging?

Q(t)= Q(f)*(1exp(t/tao))


What is the eq. for an electric field inside a spherically symmetric charge distribution?

E= Qenc/(4*pi*epsilon0*r^2)


Give 2 practical expression for flux.

flux = field*area
Flux=EA=qenc/epsilon0 

What is the eq. for a line intergal?

A=Bl=mu0*ienc


What is the BiotSavart law?

B=(mu0*i/4*pi)∫(dlXR)/R^3


What is the eq. for the force on a segment of current carrying wire?

F= iLXB


What is the equation for the magnetic dipole moment of a current loop?

mu=iA, where A is the direction of your thumb when your fingers wrap in the direction of the current.


What is the torque on a magnetic dipole in a magnetic field?

tao=muXB


What is the potential energy of a magnetic dipole in a magnetic field?

U=<mu, B>


What is the torque on an electric dipole in an electric field?

tao=pXE


What is the potential energy of an electric dipole in an electric field?

U=<p, E>


What is the magnetic susceptibility?

Bint=chi Bext


The electric and magnetic fields of accelerating charges fall of as what with respect to r?

1/ r rather than 1/ r ^2


How are the directions of E, B and r related for an accelerating charge?

EXB=r


How do you find the E of an accelerating point charge?

E=rX(rXa)


How do you find the B of an accelerating point charge?

B= rXE


How are the magnitudes of the electric and magnetic fields are related?

E=cB


If current increases or decreases in a wire, an induced electric field points _____ the acceleration.

opposite


What is displacement current?

hypothetical current that would give rise to the magnetic fields between capacitors.


What is the equation for displacement current?

i dis = mu0 epsilon0 dflux/dt


Define inductance.

V=Ldi/dt


What is eq. for the energy stored in an inductor?

U=.5Li^2


What is the LR time constant?

tao=L/R


What is the angular freq. of an LC circuit?q

omega=1/(LC)^(1/2)


What is the impedance for series LRC circuits?

Z=((XlXc)^2 +R^2)^(1/2)


What is Xl?

Xl=omegaL


What is Xc?

Xc=1/(omegaC)


What is the eq. for freq. in and LRC circuit?

f=omega/(2pi)


How do you find theta in an LRC circuit?

tan(theta)=(XlXc)/R


What colors represent hot wiring?

black and red or black tape


What colors represent neutral wiring?

white


What colors represent grounded wiring?

green and bare


What are the advantages/disadvantages of copper vs. aluminum?

copper is better
aluminum is cheaper 

Which slot is hot in an outlet?

short


What's the wavenumber?

k=2pi/lambda
