Resistivity Flashcards
1
Q
What’s resistivity?
A
How hard it is for the current to flow through the material
2
Q
What’s the formula for resistivity?
A
ρ = RA/L
ρ - Resistivity (Ωm)
R - Resistance (Ω)
A - Cross sectional area (m²)
L - Length (m)
3
Q
Why are semiconductors worse conductors than metals?
A
They have fewer charge carriers
4
Q
What happens if energy is supplied to a semiconductor?
A
- More charge carriers could be released
- The resistivity of the material decreases
5
Q
What are the examples of semiconductors?
A
- Thermistors
- Diodes
- Light dependent resistors
6
Q
What’s a thermistor?
A
- NTC (negative temperature coefficient) thermistor
- As temperature increases, resistance decreases
7
Q
What’s a superconductor?
A
- Materials have zero resistivity at and below a critical temperature
8
Q
Why is no energy wasted in a superconductor?
A
None of the energy is turned into heat
9
Q
What are the uses for superconductors?
A
- Power cables with no energy loss
- Strong electromagnets (for maglev)
- Electronic circuits with minimal energy loss
