Energy usage Flashcards
1
Q
What are the primary energy sources that humans use?
A
Fossil fuels, nuclear fuels, biofuels, wind, waves and solar power.
2
Q
What kind of energy source is electricity and why?
A
It is a secondary energy source, this is because it has got its energy from another source and has not been used from the form its found in
3
Q
What is the power (in watts) of a device or appliance a measure of?
A
The amount of energy it transfers each second
4
Q
What is the equation for energy transferred?
A
Energy transferred (J or kWh) = power (W or kW) * time (s or h)
5
Q
What is the formula for the rate at which an electrical device transfers energy?
A
Power (W) = voltage (V) * current (A)
6
Q
How do you calculate efficiency?
A
(energy usefully transferred/total energy supplied) * 100%
