EC - resistance Flashcards
what is resistance?
a measurement of how difficult it is for the current to flow
what causes resistance in a circuit
the electrons colliding with the ions and atoms in the wires and components
what has more resistance a long or short wire - why
a long wire as there are more ions and atoms for the electrons to collide with as they pass through
what is the symbol for resistance
capital R
how do you work out the total resistance of a series circuit?
add the resistance of all of the components
how do you work out the resistance in a parallel circuit
Rt = 1/R1 + 1/R2
and the total resistance equals 1/Rt
what is the relationship between resistance and potential difference
if R is increased then electrons transfer more energy so V is increased
what is the relationship between resistance and current
if R is increased there are fewer electrons passing through the circuit per second so the current is decreased
