ch 8 - electric current Flashcards
conventional current
positive to negative
electron movement in a circuit
negative to positive
electrons are the particles that allow a metal to conduct an electrical current
what is a charge carrier
a charged particle that contributes to an electric current - may be electrons, protons, ions
quantised?
a quantity is said to be quantised when it has a definite minimun magnitude and alqays comes in multiple sof that magnitude
what is current
the rate of flow of electric charge past a point
symbol - I
units - A
charge formula
charge = current * time
Q = It
what is a coulomb
one coulomb is the charge that flows past a point in a circuit in a time of 1s when the current is 1A
what is the value of elementary charge
1.6 * 10^-19 C
what is number density?
the number of charge carriers, such as free electrons, per unit volume in a material
what is mean drift velocity
the averga espeed of a collection if charges particles when there is current in a conductor
current in terms of drift velocity formula
I = nAvq OR I = nAve
I = nAvq derivation
no. of electron = n * volume of wire
no. of electron = n * Al
charge of electrons = nAl * e
I = Q/ t soo
I = nAl * e/t
substitute v = 1/t
I = nAve
ooor
I = nAvq
thinner wire =? drift velocity
greater
v proportional to I
