Electric Fields

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 × 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|/r² 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) / r² 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