Flashcards
Electricity
Cards in this deck (18)
- 1Voltage :Electrical potential energy per unit change (ex. per electron) caused by separation of charge.
* Anytime charged objects that are attracted to each other are held apart, we get voltage. Electrons will move toward + charge if a pathway is provided. - 2Voltage Equation :Voltage = Energy / Charge
V = E / Q
SL Units:
Voltage = Volts - V
Energy = Joules - J
Charge = Coulombs - C - 3Current :Is the rate of the flow of electrons. It is the amount of charge that passes a point in the circuit in one second.
* Current is caused by voltage and a complete pathway (circuit) from negative to positive. - 4Current Equation :Current = Charge / Time
I = Q / T
SL Unit: I is measured in Amperes (Amps)
Symbol: A - 5Voltage Equation Practice : A battery moves 30c of charge to the negative terminal and produces 60 J of energy. What is its voltage?Take Information out the equation:
Q = 30c
E = 60J
V = ?
Put it back in the equation:
V = E / Q
V= 60 / 30
V = 2v - 6Current Equation Practice: Calculate the current if 4500c of charge pass by in 5 minutes?Get Information out of the question:
Q = 4500c
T = 5 mins change into seconds - 300s
I = ?
Put information into the equation:
I = Q / T
I = 4500 / 300
I = 15A - 7An AmmeterAn ammeter measures the current flowing through it. It can be placed anywhere within the circuit since current is the same everywhere.
- 8A VoltmeterA voltmeter measures the difference in energy per unit charge between 2 places in a circuit, so it is placed around a power source or resistor (such as a bulb).
- 9ResistanceResistance is the ratio of voltage to current.
- The higher the resistance in a circuit, the more current is restricted.
High resistance = Lower current - 10Ohm's LawV = IR
R = Resistance
SL Unit: Ohm - Ω - 11Factors affecting ResistanceResistivity: The nature of the substances i.e. how easily electrons flow through it.
Length: The greater the length the higher the resistance.
Cross-sectional Area: The greater the diameter the lower the resistance.
Temperature: The higher the temp, the greater the resistance. - 12PowerPower refers to the amount of energy transformed in a given amount of time.
P = VI
SL Unit: Watt - W
* The brightness of a bulb is an example of power. - 13Parallel CircuitVT = V1 = V2
IT = I1 + I2
1/RT = 1/R1 + 1/R2
VT = IT RT - 14Series CircuitVT = V1 + V2
IT = I1 = I2
RT = R1 + R2 - 15Ohms LawV = IR
- 16Current Other Equations:I = Q / T
I = QE - 17Power ( Watt) Other Equations:P = VI
P = I2 R
P = V2 / R
P = E / T - 18Resistance Equation:R = P X 1 / A