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Physics SL electric fields notes
What is a coulomb?
Charge carried by an electric current of one apere in one second
Gaining and losing electrons
gaining electrons creates a negative charge and losing electrons creates a positive charge
Delocalised electrons
negativley charged & move between atoms
Electric current
rate of flow of electric charge past a cross-sectional material
current equation
I = Q/T
current flow direction
positive to negative
electron flow
negative to positive
charge carriers
charged particles moving through a material or vaccum
creation of electric field
if potential difference is applied between two points in conductor
consequences of electric field
electric force acts on charge carriers which causes charge carriers to drift on a conductor with a steady average current flow
drift speed
average speed charge carreirs move through conductor
formula for drift speed
I = NEVA
what is potential difference?
measurment of potential energy transfer from electron as it moves between two points in conductorr
voltage (potential difference)
is the work done per unit charge
formula for voltage
V = WQ if both voltages + and - given just subtract them
eV electron volt
1 ev = 1.6 Ć 10 ^-19 J and it is the amount of energy needed for an electron to move through potential difference of 1v
Direct Current
Potential difference in circuit provided by cells or batteries and flows in one direction on circuit
positive terminal
high potential
negative terminal
low potential
electrongs moving through battery
gain potential energy
allternating current
used instead of DC in high voltage devices
alternating current direction
flows one way around circuit and then reverses itself
what is the electric field?
region of space in which an electric charge feels a force
directon of electric field
same direction as electric force
electric field stregth equations
E = k|Q|/rĀ² E=F/q E=V/d
electric field stregth and force
directly proportional to the density of lines
unifrom electric field
electric force = throught and is drawn parallely with equal spaced lines
non uniform electric filed
Field stregth is stronger where more lines are closer together
what is coulombs law?
charged particles generate electric fields that exert force in any other charged particles within range
formula for electric force
F = k(q1*q2) / rĀ² F =EQ
permitivity of free space
is greater in any other material than air
like charges electric force product
positive F force therefore charges repel
opposite electric force product
negative F therefore charges atract
Note 
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