Our Sustainable Earth Flashcards
What is a renewable energy source
One which does not biodegrade and can therefore be reused multiple times
What are some examples of renewable energy sources
+ wind power (windmills)
+ tidal power (hydroelectric plants)
+ exothermic reactions
What is gravitational potential energy
The store of energy that a substance posses due to its height above ground level and it’s mass
What is the equation for gravitational potential energy and what does each symbol represent
Ep= mgh
Ep: gravitational potential energy
m: mass (ALWAYS IN KG)
g: gravitational field strength of area/planet
h: height above ground
What is gravitational field strength
The strength of gravity on a planet.
I.e. how much gravity weighs down a certain mass
What is the gravitational field strength of earth
9.8 N/Kg
What is kinetic energy
The energy possessed by an object due to its rate of movement and mass
What is the equation for kinetic mercy and what does each symbol represent
Ek= (mv2)/2
Ek: kinetic energy
m: mass (ALWAYS IN KG)
v2: velocity squared
What is the relationship between kinetic and potential energy
Ek=Ep
As energy cannot be created or destroyed, meaning that a substance can only convert the energy it possesses
What is the efficiency of an object
The measure of how successful in energy conversion an object is, based on its initial and final energy values
What is the equation for % efficiency
(Output energy/input energy) x 100
What is an unstable atom
One in which there is an increased, inequivalent number of neutrons or proton within the atoms nucleus
How can the stability of an atom be measured
proton:neutron ratio
What is nuclear fission
The process during which:one large, unstable nucleus is split into two smaller, stable nuclei by bombarding the original nucleus with neutrons.
What is released as a result of nuclear fission
+ excess neutrons
+ large quantities of energy
What is nuclear fusion
When two or more unstable nuclei collide with one another to form one, stable nucleus.
What is the name of the resultant reactions that occur due to one initial nuclear fission/fusion
A chain reaction
What is the specific heat capacity of a substance
The amount of energy required to increase the temperature of 1 kilogram of a substance by 1 degree Celsius
What is the equation to find heat energy, that involves specific what capacity + what does each symbol represent
Eh= cmΔT
Eh: heat energy
c: specific heat capacity of substance
m: mass (ALWAYS IN KG)
ΔT: change in temperature
What is the specific latent heat of a substance
The energy required to change the state of matter of 1 kilogram of a substance
What is the equation to find heat energy, that involves specific latent heat + what does each symbol represent
Eh= m Lv
Eh: heat energy
m: mass (AKWAYS IN KG)
Lv: specific latent heat of substance
Does a specific latent heat reaction require an increase in heat energy
No
Does a specific heat capacity reaction require an increase in heat energy
Yes
What is the name of the reaction when a substance transitions from a liquid—> solid
Fusion
What is the name of the reaction when a substance transitions from a liquid—>gas
Vaporisation
What are magnets
Objects with naturally occurring magnetic fields that attract or repel objects
Do like charges attract or repel
Repel
Do opposite charges attract or repel
Attract
What is an electromagnet
A core of metal with a metal coil spiral in around it, which contains a flowing current
What occurs as a result of the creation of an electromagnet
An electromagnetic field (EMF)
What can happen within an EMF
Currents can be passed between objects
What is required in an EMF
A flowing, alternating current and a moving charge
How do you increase the voltage of an EMF
+ increase the number of metal coils
+ increase the strength of the magnet
What is a transformer and what does it consist of
A contraption designed to pass currents between electrical components by creating an EMF
Consists of two metal columns with coils of wire wrapped around them, with an iron core between them
How does a transformer work
1: a current arrives in the first (primary) coil
2: this creates an EMF
3: This EMF carries the current across the gap to the second (secondary) coil and triggers a reaction which allows the current to be continued in the secondary coil
What are the two types of transformers
+ step-UP
+ step- DOWN
What is the purpose of a step-up transformer
To increase the voltage in the secondary coil
What is the purpose of a step-down transformer
To decrease the voltage in the secondary coil
What is pressure
The force exerted on a certain, enclosed area
What is the equation for pressure and what does each symbol represent
P= F/A
P: pressure
F: force (usually weight)
A: area
What is the equation of weight and what does each symbol represent
W= mg
W: weight
m: mass( ALWAYS IN KG)
g: gravitational field strength
What are the three main gas laws
+ Boyle’s law
+ Charles’ law
+ the pressure law
What is Boyle’s law
The concept that as an object decreases in volume, the pressure increases as the particles have less space to roam and therefore collide more often with each other and the container walls - with a constant temperature.
INCREASING THE PRESSURE
What is the equation of Boyle’s law
P1V1= P2V2
What is Charles’ law
The concept that by increasing the temperature of an object, the volume also increases as the particles collide with each other and the container walls with a greater kinetic energy and more frequently (due to increased movement), pushing against the container boundaries.
INCREASING THE PRESSURE
What is the equation of Charles’ law
v1/t1 = v2/t2
What is the pressure law
The concept that by increasing the temperature of an object, the interior pressure will increase as the particles with collide with each other and the walls with an increased kinetic energy and more frequently (due to increased movement) - with a constant volume.
What is the equation of the pressure law
p1/t1 = p2/t2
What is the combined gas law equation
p1v1/t1 = p2v2/t2
What must you always do when tackling problems concerning gas laws
Convert the temperature from degrees Celsius into kelvin
How do you convert from Celsius to kelvin
Add 273 to the value of the Celsius temperature
