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Core Physics > Electricity and Waves > Flashcards

Electricity and Waves Flashcards

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1
Q

Name the 4 types of non-renewable energy resources.

A

Coal
Oil
Gas
Nuclear fuels

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2
Q

Name the 7 types of renewable energy resources.

A 
Wind
Waves
Tides 
Hydroelectric 
Solar 
Geothermal 
Biofuels.
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3
Q

Describe the basic features of a power station and state how the energy transferred changes.

A

The Fuel is burnt in a boiler (CHEMICAL)
The heat energy produced is turned into steam. (HEAT)
Which then turns the turbine (KINETIC)
The turbine powers the Generator turning kinetic energy into electrical (ELECTRICAL)

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4
Q

What is different about a nuclear power station?

A

They use nuclear fission of uranium or plutonium.

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5
Q

How does wind power produce electricity?

A

By putting lots of wind turbines up in exposed places, the wind will turn the blades which turns the generator inside it.

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6
Q

PROS and CON’S of wind power.

A 
PRO'S  
no fuel costs 
minimal running costs. 
no permanent damage- if you remove the turbines the view returns to normal. 
no pollution.
CONS 
spoil the view 
very noisy 
unreliable- not always windy it would be impossible to increase the supply when there's extra demand. 
initial cost high.
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7
Q

How do solar cells produce electricity?

A

Solar cells generate electric currents directly from sunlight.

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8
Q

PROS and CONS of solar cells.

A 
PROS 
No pollution 
very reliable - in the day time 
energy is free 
running cost very low 
good at generating electricity on a small scale.

CONS
Initial cost high.
Not practical or to expensive on a large scale e.g connecting them to the national grid.

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9
Q

How does hydroelectric power generate electricity?

A

Rainwater is caught in a big dam and allowed through turbines to generate electricity.

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10
Q

What are the PRO’S and CON’S of hydroelectric power?

A

PROS
No pollution
provides immediate response to an increased demand for electricity.
reliable
no fuel
minimal running cost.
Can be useful to generate electricity on a small scale in remote areas.
CON’S
Initial cost very high
big impact on environment- flooding, loss of habitat.
Not attractive when the dam dries up.

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11
Q

What do pumped storage systems do?

A

They give extra supply just when it is needed.
Power stations keep there boilers running all night even though demand is very low, so there is a lot of extra electricity at night. Pumped storage systems can store this spare energy for later use. The spare night-time electricity is used to pump water up to a higher reservoir, this can then be released quickly during periods of peak demand. Pumped storage systems use the same idea as hydroelectric but it isn’t away of generating power its a way of storing energy.

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12
Q

How does wave power generate electricity? What are the PRO’S AND CON’S?

A 
As waves come in to the shore, they provide an up and down motion which can be used to drive a generator. 
PRO'S
No pollution
good for small scale electricity
no fuel cost
minimal running costs
CONS
Hazard to boats
spoils view
unreliable 
initial cost high
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13
Q

How do tidal barrages generate electricity? PROS AND CONS

A

Tidal barrages are big dams built across rivers with turbines in them. As the tide comes in it fills up the dam and powers the turbines, the water can then be allowed out through the turbines at a controlled speed.
PROS
No pollution
reliable
Good at storing energy and releasing at peak demand.
no fuel costs
minimal running costs.

CONS 
preventing free access by boats 
spoils views
alters habitats 
high initial cost.
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14
Q

How does Geothermal energy generate electricity?

PROS and CONS

A 
Only possible in volcanic areas where hot rocks lie quite near the surface. The radioactive decay produces steam and hot water which rises to the surface and drives a generator. 
PRO'S 
free energy
no pollution 
can be used to heat buildings directly.

CON’S
not very many suitable locations for power plants.
cost of building power plant high compared to the amount of energy you can get out of it.

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15
Q

What is CCS and what is it used for?

A

Carbon capture and storage is used to reduce the amount of carbon dioxide building up in the atmosphere.
Carbon dioxide is removed from power stations before it is released into the atmosphere and stored into empty gas or oil fields.

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16
Q

What is the National Grid?

A

a network of pylons and cables that cover the whole of Britain, getting electricity to homes everywhere.

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17
Q

What is the problem with a high current?

A

You lose lots of energy through heat in the cables.

18
Q

How can we reduce heat lost through cables?

A

By boosting the voltage up high and keeping the current low.

19
Q

What do step-up and step-down transformers do?

A

The step up transformer increases the voltage up at one end for efficient transmission and then the step down transformer brings the voltage back down to safe, usable levels in homes.

20
Q

What is the amplitude of a wave?

A

The displacement from the rest position to the crest.

21
Q

What is the wavelength? give the unit

A

The length of a full cycle of the wave, from crest to crest. metres M

22
Q

What is the frequency of a wave? give the unit

A

the number of waves per second Hz Hertz

23
Q

What type of vibration do transverse waves have?

A

Transverse waves have vibrations perpendicular to the direction of energy transfer of the wave.

24
Q

Give examples of transverse waves.

A

Light
EM waves
ripples on water

25
Q

What type of vibrations do longitudinal waves have?

A

Longitudinal waves have vibrations that are parallel to the direction of energy transfer of the wave.

26
Q

What is the equation for wave speed?

A

speed= frequency*wavelength

m/s Hz m

27
Q

Give examples of longitudinal waves.

A

Sound

shock waves

28
Q

What can all waves do?

A

all waves can be reflected, refracted and diffracted.

29
Q

What is the law of reflection?

A

the angle of incidence= the angle of reflection

30
Q

What is diffraction?

A

When a wave passes through a gap or passes and obstacle, the wave will diffract (spread out).
If the gap is narrower or the wavelength is long the wave will spread out more .

31
Q

How does maximum diffraction happen?

A

when the gap is the same size as the wavelength.

32
Q

What is refraction?

A

When a wave crosses a boundary between two substance it changes direction, it is refracted.

33
Q

What happens if the wave is travelling along the normal?

A

It is NOT refracted, they don’t change direction they only change speed.

34
Q

Name the seven basic types of waves in the Electromagnetic spectrum

A 
Radio
Microwave
Infra red
Visible 
ultraviolet
x-rays
gamma rays
35
Q

What do the waves in the EM spectrum all have in common?

A

They travel at the same speed of 3*10^8
They all travel in a vacuum.
They can all be reflected, refracted and diffracted.

36
Q

What can the waves from the EM spectrum be used for?

A

Radio - communication
Microwave- satellite communication and mobile phones.
Infra-red- remote controls and optical fibres.
Visible- photography.

37
Q

What is the Doppler Effect.

A

The frequency of a source moving towards you will seem higher and its wave length will seem shorter.
The frequency of a source moving away from you will seem lower and its wavelength will seem longer.

38
Q

What does red shift suggest about the galaxies?

A

That all the galaxies are moving away from us very quickly, more distant galaxies have greater red- shifts than nearer ones , this means that more distant galaxies are moving away from us faster than nearer ones.
This provides evidence that the whole universe is expanding.

39
Q

What is the big bang theory?

A

All the matter and energy in the universe was compressed into a very small space which exploded from the single point and started expanding.

40
Q

What does CMBR stand for? what is it about?and why is the big bang theory is the only theory to explain it?

A

CMBR is the cosmic microwave background radiation.
When the universe was still extremely hot it emitted high frequency gamma rays, but as the universe has expanded and cooled this radiation has dropped in frequency and is now seen as microwave radiation. Therefore as the universe has expanded the waves have stretched and created microwaves.

Core Physics (2 decks)

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