Energy Flashcards
Forms of energy
Magnetic Kinetic Heat/thermal Light Gravitational potential Sound Chemical Electrical Elastic potential Nuclear (Most, kids, hate, learning, G, C, S, E, energy, names)
Stores of energy
Kinetic-in a moving object
Chemical-a fuel or battery
Gravitational-an object above ground
Elastic/strain-a stretched or squashed object
Thermal-due to the substances temperature
Magnetic-2 separated magnets (attract/repel)
Nuclear-radioactive decay
Energy transfers
Waves
Heating
Current(electric)
Mechanical
Example of change in energy store
Chemical TO electric current in wires TO energy transferred to surroundings TO BOTH light waves AND increase in thermal energy stores of surrounding
Specific heat capacity
How many joules of heat energy needed to raise the temperature of each kg by 1°C
Specific heat capacity equation
Mass (m) x Temperature change (Q)
Work done equation
W = F x d
F=force,N
D=distance,m
1N/m =
1 joule
10N/m =
10 joules
2 types of light bulbs
- CFL, compact fluorescent light bulb
- Filament light bulb
CFL, compact fluorescent light bulb
Transfer much less energy as heat compared to filament bulbs
Why good?
Wasting energy is a major problem of the world as energy resiurces become less available
Filament light bulb
Transfers a large amount of energy
Why problem?
The useful energy required from a light bulb is light but instead there is too much heat
Efficiency =
Useful energy out
———————– x 100
Total energy supplied in
Convection
The movement caused within a fluid by the tendency of hotter and therefore less dense material to sink under the influence of gravity, which consequently results in transfer of heat
Conduction
The process by which heat or electricity is directly transmitted through the material of a substance when there is a difference in temperature or electrical between adjoining regions, without movement of the material
