Whole of aqa physics Flashcards
What is wasted energy
When energy is dissipated into the surroundings
How to be energy efficient in a house
Cavity wall insulation
double glazing
loft insulation
carpets
curtains
draft excluders
What does renewable mean
not going to run out can get more e.g. solar wind water. also dont release co2
What is an Independent Variable
Something that is changed
What is an dependent variable
something that is measured
what is a controllable variable
something that is kept the same
What is finite
going to run out cant get more e.g. fossil fuel coal oil gas
Disadvantages to solar power
Doesn’t work during night and isn’t god on cloudy days or wintry days and expensive
Disadvantages to wind power
People dont like them dont work on non windy days
Disadvantages to tidal and wave energy
can be disruptive to environment and hydro electric dam involves flooding large area disrupts habitats
Disadvantages to geothermal energy
Only used in volcanic countries
Advantages to fossil fuels
Readily available cheap source of electricity
things like coal power stations have a short start up time
Disadvantages of fossil fuels
Take millions of years to form
Heavily polluting
What is charge
Value for electricity flowing in a circuit
Measured in coulombs, C
What is current
Flow of electrons
Measured in An ampere or amp,
What is potential Difference
Pushes current around
Measured in Volts
What is Resistance
slows downs the current
Measured in ohms
Equation for Power
P(watts)= V(volts) x I(amps)
power= potential difference x current
Equation for power current squared
p= I^2 x R
power= amps x ohms
Equation for energy
E= P x T
Power x time
Joules=power x watts
Equation for energy (2)
E= Q x V
energy= charge x potential diff
Q= coulombs
Step up transformer
Turns low voltage into high voltage so energy can move through a system with less energy loss= more efficient
Step down transfromer
takes High voltages and turns it down to low voltage to allow it to be safe in our homes
What is density
Mass in a set volume
equation for density
p=m/v
P=density kg/m^3
M=mass
V=volume
Specific heat capacity
Amount of energy needed to raise the temperature of 1kg of the substance by 1degree Celsius.
Equation for SHC
change in energy= mass x SHCx Change in temp
Triangle e= m x c x triangle o
Specific Latent Heat
Amount of energy required to change the state of 1kg of the substance with no change in temperature.
Equation for specific latent heat
E= m x l
energy=mass x specific latent heat
j=kg x J/kg
Internal Energy
The total energy stored inside a system by the particles that make up the system due to their motion and positions
What is an ion
an atom that has lost or gained an electron
What is an Isotope
an atom that has diff number of neutrons but same protons and electrons
History of the atom
Rutherford- positive centre
Chadwick=neutrons
Bohr-nuclear model
Alpha Radiation (helium nuclei)
Radiation is large
Highly ionising
No penetration
Paper and skin can stop alpha
Plum pudding model
A large positive blob with negative bits dotted throughout
Beta Radiation (electron)
Radiation is moderate
Moderately ionising
Moderately penetrating
Aluminium can stop beta
Gamma Radiation (electromagnetic wave)
Radiation is small
Not Ionising
Highly penetrating
Lead can stop gamma
What does ionising mean
How good it is at turning something into an ion
What measures Radiation
Geiger muller tube
Unit for radiaiton
Becquerels (bq)
Half life
Time it takes the radioactive atom to decay
