Studied by 4 people
Q
Charge
Q units
Coulombs
Coulomb’s law
KqQ/r²
Q positive
E and F parallel
Q negative
E and F opposite
Net electric field
Add all electric fields
Voltage also
Potential difference
V net
Add all v
Along equipotential lines
Constant potential
Work required to move charge on equipotential line
0
Direction of equipotential lines
Perpendicular to force and field
Direction of movement that uses work
Same direction as force
Closer equipotential lines
Greater field
Electric flux
Electric field through surface
Outward flux
Positive
Inward flux
Negative
Flux from charges outside surface
0
Flux is proportional to
Charge enclosed
E field lines begin at
Positive charges
E field lines end at
Negative charges
E field at center of sphere
0
E field between center and radius
Increases linearly
Maximum e field at
Surface of sphere
E field outside of sphere
Decreases exponentially
Property of metals/conductors
Charge can move freely
E field in conductor
0
Any Gaussian surface completely inside a conductor encloses a net charge of
0
Electric flux through Gaussian surface completely inside conductor
0
On a conductor charge can only exist on
The surface
Net charge on conductor
Sum of charge on surface
E field on a metal
Constant
Potential difference on a conductor
0
E field outside of charged sphere equation
Kq/r²
E field at center of ring of charge
0
Acceleration due to electric field
QE/m
Change in speed due to potential difference
½ m(vf-vi)²
Unit of current
Amperes
Conventional current flows from
High to low potential
Conventional current is movement of
Positive charges
Resistance units
Ohms
Ohmic resistors
Obeys ohms law
Graph of I(V)
Straight line
Graph of I(R)
1/x
Resistors use
Current
Series circuit I net=
Equal I
Potential across wire
Constant
Current entering intersection =
Current leaving intersection
Connect voltmeter in
Parallel
Resistance of voltmeter
High
Connect ammeter in
Series
Resistance of ammeter
Low
Use Kirchhoff’s laws when
More than one battery
Node rule
Current entering intersection equals current leaving
Loop rule
Total potential differences around closed loop must be 0
Charge on capacitor plates are
Equal and opposite
Capacitance units
Farads
Voltage between capacitor plates
Constant
Energy stored in capacitor equals
Energy required to charge it
Adding more charge to a capacitor does what to the voltage
Increases it
Adding a dielectric affects energy by
Decreasing energy stored
Adding a dielectric affects capacitance by
Increasing it
Dielectric affects electric field by
Doesn’t change field
Dielectric affects charge by
Increasing it
As capacitor discharges the charge across it
Decreases
Charge across discharged capacitor will eventually be
0
At t=0 charge and voltage across capacitor is
0
Current across capacitor
Decreases with time
Increasing distance between capacitor plates will
Decrease capacitance
Time constant RC circuit
RC
Magnetic field units
Teslas
Magnetic force on a charge at rest
0
Magnetic force on charge is 0 when charge is moving
Parallel to field
Radius of charged particle path due to centripetal force in magnetic field
mv/qB
Force of a straight wire in a constant magnetic field
IlBsintheta
Wires with same direction of current
Attract
Wires with opposite direction of current
Repel
Torque in section of loop parallel to field
0
Magnetic flux units
Webster
Direction of induced emf
opposite of change
Current in circuit with inductor immediately after closing loop
0
After a long time the inductor acts like a
Wire
Time constant for LR circuit
L/r
Work
Change in energy
Circle
Out of page
X
Into page
E field due to sphere of uniformly distributed charge
Kq/a²
E inside sphere
0
E field due to non uniform line of charge
Integral of kbxdx/(L+a-x)²
E field due to uniform arc of charge
1/2pie(lambda/R)sintheta
E field due to uniformly charged sphere inside sphere
Kqr/R³
E field due to uniform line of charge
Kq/(a(l+a))
Voltage across cylindrical capacitor
2kq/L(ln(b/a))
Loop and current same direction
V=-IR
Loop and current opposite directions
V=IR
Loop exits positive terminal of battery
Add V
Loop exits negative terminal of battery
Subtract V
Charge on capacitor
Cv(1-e^(-t/RC))
Discharging a capacitor
Qe^(-t/RC)
Magnetic field around wire
muI/2pir
V for bar moving in B field
-Bhv
Note 
Flashcard (40)