physics p1 Flashcards
(22 cards)
current
Flow of electrons through a circuit
Measured in amps using an ammeter
potential difference
amount of energy transferred through 2 points in a circuit
measured in volts using voltmeter
charge
size of electrical current is rate of flow of electrical charge
measured in coulombs
resistance
potential difference required to push a current through a component
measured in ohms
Diode
LED
only allow current through in one direction
heavily resistant if not
3 types of wire and function
brown-live, carries potential difference from supply (around 230v)
blue-neutral, completes circuit with live wire
green/yellow-earth, safety
what is national grid
system of connecting power stations to homes through power cables
what are 2 transformers, use
Step-up transformer, increase potential difference therefore less energy is lost
Step-down transformer, reduce potential difference so it is safe to enter homes
direct current and alternating current
direct - current from cell travels in one direction
alternating - constantly changes direction
thermistor
resistance decreases if temperature increases
use: computers, thermostat
light dependant resistor
in dark - high resistance
in light - low resistance
kinetic energy
energy stored in moving objects
elastic potential energy
energy used to stretch an object .e.g spring
gravitational potential energy
energy stored by an object due to its height above the earth
specific heat capacity
amount of energy required to heat 1kg of a substance by 1 degree
thermal energy
energy stored due to an objects temperature
work done
whenever energy is transferred from one object to another
power
rate at which energy is transferred (work done)
measured in watts
efficiency
how much energy input is actually used
what are 3 fossil fuel energy sources + positives and negatives
Oil,Coal,Gas
P reliable, cheap abundant
N release Co2, finite
nuclear power
non-renewable
run on uranium and plutonium
dosen’t release co2, reliable
contains radioactive material, expensive
