Lesson 1: Intro to Nature of Electricity Flashcards
What causes electricity?
Electrons
What happens to the electrons when they are in their most stable state?
The number of electrons is equal to the number of protons
Electricity is measured in?
Coulombs
1 electron is equal to?
-1.6022 x 10^-19 C
What are the two types of current flow?
Direct and Alternating Current
What type of current flow has only one direction of electricity where its path is closed?
Direct Current
What type of current flow where electrons are free to go into different direction?
Alternating Current
What are the parts of the electrical circuit variable?
Current, Voltage, and Resistance
It is the rate of flow of electricity or aka “the electricity” itself?
Current
What is the symbol and unit for current?
I and Ampere (A) or J/C
It is the work per unit charge necessary to bring/push a charge from a negatively charged plate to a positively charged plate.
Voltage
What is the symbol and unit of voltage?
E or V and Volt (V) or C/s
It is the ability of a material to limit the flow of electrons. Aka “The Blocker”
Resistance
What is the symbol and unit of resistance?
R and ohms (Ω ) or Js/C^2
What is formula of Ohm’s Law?
V=IR
What material can electricity pass through easily as it has low electrical resistance?
Conductor
What substances have high electrical resistance compared to conductors?
Resistors
What substances do electricity can’t pass through due to the absence of free electrons?
Insulators
It is the measure of the opposition to current flow in an electrical circuit.
Resistance
Who is the German physicist who studied the relationship between voltage, current, and resistance where Ohms Law is named after him?
George Simon Ohm (1784-1854)
What is the formula of resistance?
R = pL/A
If the length of the conductor is long, what happens to the resistance?
Increase
If the length of the conductor is short, what happens to the resistance?
Decrease
What is the relationship of the length of the material to resistance?
Directly proportional
If the cross sectional area (A⬇️) of the material is thin, what happens to the resistance?
Increase
If the cross sectional area (A⬆️) of the material is thick, what happens to the resistance?
Decrease
What is the relationship of cross-sectional are to the resistance?
Inversely proportional
What is the unit for resistance (R)?
Ohms (Ω)
What is the unit for cross-sectional area (A)?
square meter
What is the unit for lenght (L)
Meter
What is the unit of resistivity coefficient (p)?
Ohm-meter (Ω)
1000 Mill is equal to?
1 inch
1000 CM is equal to?
1 MCM
It is the measurement of how easily a current can flow through the component which is measured in Siemens (S).
Conductance
What is the inverse of the resistivity and is usually denoted by the Greek letter (σ) meaning Sigma?
Conductivity
What is the symbol for temperature coefficient?
α
What is the effect of a positive temperature coefficient on the resistance of a conductor?
Resistance will increase; R⬆️= T⬆️ and/or R⬇️= T⬇️; They are directly proportional
What is the effect of a negative temperature coefficient on the resistance of a semi-conductor or insulator?
They are inversely proportional. If R⬆️ = T⬇️ and If R⬇️ = T⬆️
