P1 Energy Flashcards
What are the 3 key words to describe energy transfers?
Increases, decreases, dissipates
What is the law of the conservation of energy?
Energy can’t be created or destroyed
Name the 8 energy stores:
- Thermal
- Electrostatic
- Chemical
- Magnetic
- Nuclear
- Gravitational potential
- Kinetic
- Elastic potential
What is work done equal to?
Energy transferred
What happens when work is done on an object?
Work is done on an object when a force makes an object move
Name the 4 energy transfers:
- Mechanical
- Electrical
- Thermal
- Radiation
What is conduction?
The flow of electrons through a substance, transferring heat or electricity
What is convection?
Heat is transferred from one place to another - heat energy is transferred hot to cold
What direction is heat transferred?
Hot to cold
Why can no device have over 100% efficiency?
According to the law of conservation of energy, you can’t get more energy from a machine than you put into it
What is the symbol for energy?
J
What is the unit for energy?
Joules
What is the symbol for mass?
m
What is the unit for mass?
kg
What is the symbol for velocity?
v
What is the unit for velocity?
m/s
What is the unit for gravitational field strength?
N/kg
What is the standard gravitational field strength?
10N/kg
What is the symbol for power?
W
What is the unit for power?
Watts
What is the unit for charge?
Coulombs
What is the symbol for charge?
Q in equations, c as shorthand for coulombs
What is the symbol for current?
I in equations, A as shorthand for amps
What is the unit for current?
Amps
What is the symbol for time?
s
What is the unit for time?
Seconds
What is the symbol for potential difference?
V
What is the unit for potential difference?
Voltage
What is the symbol for resistance?
R
What is the unit for resistance?
Ohms - Ω
What is the symbol for heat capacity?
c
What is the symbol to represent change in energy?
θ
What is a closed system?
A system in which no energy transfers take place in or out of the energy system
What is wasted energy?
Energy used in less useful ways or dissipated to surroundings
What is the independent variable?
What we change
What is the dependent variable?
What we measure
What is the control variable?
What we keep the same
What are the 6 stages of burning fossil fuels to produce electricity?
- Burn fuel
- Heats water
- EVAPORATION: water becomes steam
- Steam turns turbine/propeller
- Spins an electromagnet in a coil of wire
- Generates a flow of electrons
What are the 8 energy resources?
- Wind
- Wave
- Fossil Fuel
- Nuclear
- Solar
- Geothermal
- Hydroelectric
- Tidal
What are the positives of wind energy?
Renewable, no CO2 produced
What are the negatives of wind energy?
Unreliable, unsightly (not aesthetically pleasing)
What are the positives of wave energy?
Renewable, no CO2 produced
What are the negatives of wave energy?
Not reliable - waves are temporary
What are the positives of fossil fuels?
Reliable, cheap to produce
What are the negatives of fossil fuels?
Non-renewable, CO2 emissions
What are the positives of nuclear power?
Constant, reliable
What are the negatives of nuclear power?
Causes pollution, not reliable
What are the positives of solar power?
No CO2 emissions, renewable
What are the negatives of solar power?
Unreliable - not always sunny
What are the positives of geothermal sources?
Renewable, reliable, no CO2 emissions
What are the negatives of geothermal sources?
Can only be produced in some places, rocks may cool down over time
What are the positives of hydroelectric sources?
Renewable, no CO2 emissions
What are the negatives of hydroelectric sources?
Expensive, requires a lot of space
What are the positives of tidal power?
Renewable, no CO2 produced
What are the negatives of tidal power?
Unreliable
What is specific heat capacity a measure of?
How easily a material heats up
What does BUGS stand for?
Box Underline Glance Scribble
What does ESAU stand for?
Equation Underline Answer Unit
What is the equation for kinetic energy?
0.5 x m x v^2
What is the equation for elastic potential energy?
0.5 x k x e^2
What is the equation for gravitational potential energy?
m x g x h
What is the equation for specific latent heat?
Energy / mass
What is the equation for specific heat capacity?
m x c x θ (change in temp)
What is the equation for efficiency?
Useful out / Total in x 100
What is the equation for power?
Energy / time
What is the equation for resistance?
Potential difference / current
What is the equation for work done?
Power x time
What is the equation for energy transferred?
Charge flow x potential difference
What is the purpose of lubrication?
To improve efficiency - reduce waste energy by reducing/limiting friction
What are the 3 prefixes for big in ascending order?
- Kilo
- Mega
- Giga
What are the 3 prefixes for small in descending order?
- Milli
- Micro
- Nano
How do you convert to milli?
x10^-3
How do you convert to micro?
x10^-6
How do you convert to nano?
x10^-9
How do you convert to kilo?
x10^3
How do you convert to mega?
x10^6
How do you convert to giga?
x10^9
What is nuclear energy?
Energy stored in atoms
What is magnetic energy?
Energy stored in magnetic fields
What is electrostatic energy?
Energy used when a balloon goes static
What is kinetic energy?
Energy stored in movement
What is chemical energy?
Energy stored in chemicals or food
What is thermal energy?
Energy stored in heat
What is gravitational potential energy?
Energy stored in high up things
What is a mechanical transfer?
A transfer by a force
What is a thermal transfer?
A transfer by passing heat from one object to another
What is a radiation transfer?
A transfer by waves
What is an electrical transfer?
Transfer by moving charge from one place to another
A lower/smaller specific heat capacity, a ————–
Smaller amount of energy to heat up
What are the stages of convection:
- Cold air
- Adding heat - temperature increases
- Particles vibrate more
- Particles spread out
- Temperature decreases