4.1: Electricity : Charge and Current Flashcards
Define: Current
Rate of flow of Charge (I=Q/t)
Define: Potential Difference
Work Done per unit charge moved (V=W/Q)
What 3 factors affect Mean Drift Velocity?
- Area
- Amount of Electrons
- Current
Define: Resistance
A competent has a resistance of 1Ω when a potential difference of 1V makes a current of 1A flow through it
What 3 factors affect Resistance?
- Length
- Area
- Resistivity
Describe 1 factor that affects Resistivity(ρ)?
-Temperature, increases so does Resistivity
List 3 semi-conductor components
- Light dependant resistor(LDR)
- Thermistor
- Diodes(LED)
Describe the characteristics of resistance on a Thermistor
- Resistance decreases as temperature increases
- Increasing current = Increasing temperature
Describe the characteristics of resistance on a LDR
-Resistance decreases as light intensity increases
NOTE:Light provides energy therefore releases more energy
Describe the characteristics of a Diode
3 factors
- Let current flow in 1 direction(Forwards bias)
- Threshold Voltage must be met for conduction
- Reverse bias has large Resistance
Define: Power
Rate of work done(Transfer of energy P=e/t)
How many joules is 1kWh equivalent to?
3.6 million J
How do you find kWh?
Power(in kiloWatts) x time(hours)
How do you find out the cost of electricity
Cost = No. of units x price per unit
What are the environmental impacts of burning fossil fuels
-Release greenhouse gases and contributes to global warming and Sulfur dioxide = acid rain
