Our Sustainable Earth Flashcards by Angus hasler

What is a renewable energy source

One which does not biodegrade and can therefore be reused multiple times

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What are some examples of renewable energy sources

+ wind power (windmills)
+ tidal power (hydroelectric plants)
+ exothermic reactions

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What is gravitational potential energy

The store of energy that a substance posses due to its height above ground level and it’s mass

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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

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What is gravitational field strength

The strength of gravity on a planet.

I.e. how much gravity weighs down a certain mass

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What is the gravitational field strength of earth

9.8 N/Kg

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What is kinetic energy

The energy possessed by an object due to its rate of movement and mass

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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

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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

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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

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What is the equation for % efficiency

(Output energy/input energy) x 100

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What is an unstable atom

One in which there is an increased, inequivalent number of neutrons or proton within the atoms nucleus

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How can the stability of an atom be measured

proton:neutron ratio

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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.

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What is released as a result of nuclear fission

+ excess neutrons

+ large quantities of energy

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What is nuclear fusion

When two or more unstable nuclei collide with one another to form one, stable nucleus.

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What is the name of the resultant reactions that occur due to one initial nuclear fission/fusion

A chain reaction

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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

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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

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What is the specific latent heat of a substance

The energy required to change the state of matter of 1 kilogram of a substance

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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

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