Resistivity Flashcards
What is the equation for resistivity
p = RA/L
What is resitivity measured in
ohm metres
What is a conventional current
original current from positive to negative
What is the calculation for area (A)
pi d^2 divided by 4
What happens when temperature increases in metals
Resistance increases
What happens when temperature increase in semiconductors
Resistance decreases
What are the uses of a thermistor
heat sensors in laptops, car engines, kettles
What does the IV graph of a thermistor look like
inverse to filament bulb, as voltage increase current increases at a greater rate
What is superconductivity
0 resistance once material dropped below certain temperature
What is the temperature called where resistance becomes 0
critical temperature
What are superconductors useful for
requiring large electric currents like electromagnets and reducing energy losses
