Electricity Flashcards
How do we use electricity?
-Lights
-Communication
-Heat
-Medical Devices
-Appliances
What is the transfer of electrons called?
Static electricity
What are the three laws of charges?
-Unlike charges attract
-Like charges repel
-Charged objects attract uncharged (neutral) objects
What are conductors? What are three examples?
Conductors are materials that allow charges to move freely. Examples of these are copper wiring, tap water, and metals.
What are insulators? What are three examples?
Insulators are materials that do not allow charges to pass easily through them. Examples of these are rubber, plastic, and wooden materials.
What are semiconductors?
Semiconductors are materials that have:
-Higher conductivity than insulators
-Lower conductivity than metals
What are superconductors?
Materials that offer little, if any, resistance to the flow of charge.
What is electric discharge?
Rapid redistribution of charge between two objects.
What is grounding?
Means to connect to the earth so charge build ups are prevented.
What are ways you can prevent static buildup?
-Humidifiers
-Dryer sheets
-Anti static sprays
-Grounding wires
What is a circuit?
A circuit provides a continuous for electrical charges.
What are the four main parts in a circuit and what are examples of each?
-Source (battery)
-Conductor (wires)
-Load (light bulb)
-Control (switch)
What is current?
Current is the amount of charge that passes a point in a conducting wire every second.
What is voltage? What is it also called?
The change in energy between two points in a circuit (energy is lost going through a device). Voltage is also called potential difference.
What is resistance?
The property of a substance to hinder the motion of charge.
What factors affect resistance?
-Length of wire
-Cross-section area
-Temperature of wire
-Material
What are resistors?
Materials used to control current or voltage.
What are the two types of circuits and what is the difference?
-Series circuit - have only one current path
-Parallel circuit - have several paths
What are the two laws of thermodynamics?
- Energy cannot be created or destroyed, only converted from one form to another
- In any energy transfer, some energy is lost to the surroundings as waste energy.
What is a thermocouple?
a loop of two wires made of different types of metals.
What is a thermo-electric generator?
A device that uses thermocouples to create usable electricity.
What is the Piezoelectric effect?
Sound produced when an electric current passes through a quartz crystal.
How can light be used to create electricity?
Using a photovoltaic cell (solar cell).
What is a Electrochemical Cell?
A device that converts energy stored in chemicals (metals) into electrical energy.
What are the two main parts of a Electrochemical Cell?
- Electrodes (two different metals)
- Electrolyte (conductor - conducting solution)
What are the three types of cells?
- Primary - single use
- Secondary - rechargeable
- Fuel - a cell that will run indefinitely with the addition of fuel
What is an Electric Generator?
A device that converts mechanical energy (motion) into electrical energy.
What are the two main parts of an electric generator?
- Coil of Wire
- Magnet
How do you increase the output of a generator?
-Faster movement
-Stronger magnet
-More coil of wire
What is the difference between alternating and direct current?
Alternating:
-Current that switches direction regularly
-Household use (plug-ins)
-Easy to increase or decrease voltage (increase to travel through wires, decrease in homes)
Direct:
-Current that flows in only one direction
How do you increase the strength of an electromagnet?
-Stronger current
-More wire
-Better quality core (more iron)
What is a motor?
A device that converts electrical energy into mechanical energy.
What are transformers?
Either increase or decrease the voltage of this transmission. Remember, alternating current is easier to increase or decrease than direct current.
Why are circuit breakers and fuses (in older houses) important?
This is because if the current exceeds a safe level, the metal inside bends, tripping the breaker, opening the circuit, and stopping the current. This is to prevent fires.
What is efficiency?
The efficiency of a device or an energy conversion is the ratio of useful output energy to the total input energy.
What are safety tips when dealing with electrical materials?
-Don’t overload an outlet or circuit
-Unplug appliances before working on them
-Replace frayed cords
-Never use appliances near water
-Don’t touch live wires
What are examples of Renewable power sources?
- Hydroelectric plant
- Geothermalelectric plant
- Biomass
- Windmills
- Solar plant
What are examples of Non-renewable power sources?
- Fossil Fuels
-Gas, oil, coal - Nuclear power
-Radioactive elements
What are the types of wastes created by energy sources? Briefly describe the,.
- Nuclear waste - From Nuclear Fission (splitting atoms)
-Nuclear Fusion (combining atoms) doesn’t create waste - Gas pollution - Many fossil fuels give off gas waste
- Thermal pollution - Heat is given off to the environment
What are the advantages and disadvantages of power plants?
