9.7-9.11 Energy Power Resistance 2 Quizlet Cards Flashcards
What are the units of resistivity?
Ωm
What is ρ in R = ρL / A?
The resistivity of the material
What is L in R = ρL / A?
The length of the wire.
What is A in R = ρL / A?
The cross-sectional area of the wire
As a metal gets hotter what happens to its resistivity?
It increases.
What is meant by a negative temperature coefficient component?
One in which the resistance drops as temperature increases.
Why does resistance of a thermistor fall as temperature increases?
The number density of charge carriers increases.
What are thermistors commonly used in?
Temperature sensors.
Why does the resistance of an LDR as light intensity changes?
Light increases the number density of charge carriers in the LDR.
What are LDRs commonly used in?
Light intensity sensors.
What happens to the resistance of an LDR as light intensity increases?
It decreases.
What is a kilowatt-hour (kWh)?
The energy supplied when 1kW of power is supplied for 1 hour.
How many Joules are equivalent to a kWh
3.6MJ
