current electicity

Question 1

convection current

Answer 1

the opposite direction to electron flow

Question 2

electric current

Answer 2

rate of flow of electric charge

I=Q/t

Question 3

electromotive force (emf) of an electrical source

Answer 3

is the work done by the source in driving a unit charge around a complete circuit
e=W(in J)/Q
in series: the resultant emf is the sum of all emf cells
in parallel: resultant emf is equal to that of a single cell

Question 4

potential difference

Answer 4

work done to drive a unit charge through a component

V=W/Q

Question 5

resistance

Answer 5

ratio of the potential difference across it to the current flowing through it
R=V/I
higher the resistance, smaller the current

Question 6

ohms law

Answer 6

current passing through a metallic conductor is directly proportional to the potential difference across it provided that physical conditions remain constant
V/I = R = constant

Question 7

ohmic conductors

Answer 7

constant gradient (I against V graph)

Question 8

non ohmic conductors

Answer 8

filament lamp - as current increase, generate more heat, temp increase, resistance increase
semiconductor diode -

Question 9

resistance of metallic conductors

Answer 9

ohmic or non ohmic generally increases with increasing temperature

Question 10

resistivity

Answer 10

R=p(l/A) , p is a resistivity, a constant