Unit 2 - Electricity Flashcards
disadvantages of nuclear power plants
- radioactive waste is produced, which is difficult to dispose of safely.
- It’s expensive to set up and close down nuclear power stations.
- There is a risk of radiation leaks and catastrophes.
define current
rate of flow of charge
what carries charge
electrons
other names for voltage
emf (electromotive force)
potential difference
from which terminal does current flow
positive to negative
define voltage
the amount of energy needed to transfer one coulomb of charge between 2 points
define direct current
a current with the same current and direction
define alternating current
a current with changing magnitude and direction
define resistance
A measure of how hard it is for current to flow through a material or component
what is a live wire
Wire in a circuit with a high voltage compared to the other wires
what is a neutral wire
Wire that completes the circuit; the voltage is always compared to this wire
what is an earth wire
Wire in a circuit that prevents electrical shock. These are only needed in devices with metal cases.
what are insulators
Materials that do not allow a current to flow, they do not contain free moving electrons .
for example plastic or rubber
what is double insulation
A protection method which avoids the need for an earth wire. Two layers of insulating material, usually rubber and plastic, are used.
what is power
energy transferred per second
