Electricity - Resistance Flashcards
1
Q
Resistance (R)
A
ohms (Ω)
2
Q
ohms Law
A
The potential difference across a component is directly proportional to the current through it, provided the resistance remains constant (i.e. V ∝ I∴ V = RI).
3
Q
Resistivity ( ρ)
A
ohm - meters (Ωm)
4
Q
Resistivity equation
A
ρ = RA/I
5
Q
Resistors in series
A
∑ RS = R1 +R2 +R3 …
6
Q
Resistors in parallel
A
1/∑RP = 1/R1 + 1/R2 +1/R3 …
7
Q
superconductors
A
Materials with no electrical resistance (at and below the critical temperature) and therefore no power losses (as P = I2R). Used in high-power electromagnets and cables (e.g. MRI scanners / particle accelerators / mag-lev trains).
