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Physics > Energy and Energy Resources > Flashcards

Energy and Energy Resources Flashcards

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1
Q

Useful energy is…

A

.. energy in the form and place we want it

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2
Q

What happens when energy dissipates?

A

It becomes less and less useful

It heats up the surroundinds

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3
Q

How does the gravitational potential energy of an object change?

A
  • when it goes UP, it INCREASES

- when it goes DOWN, it DECREASES

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4
Q

What are the best conductors of energy and why?

A

Metals

- they have free electrons that move up and down the material

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5
Q

What is an Elastic Potential Energy store?

A

The energy stored in a springy object when it is stretched or squashed

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6
Q

Disadvantages of Nuclear Power

A
  • used fuel rods contain radioactive waste
  • an explosion would disperse radioactive waste over a wide area
  • stations are expensive to build, run and decommission
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7
Q

Work done is …

A

.. when an object moves as a result of a force

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8
Q

How is energy transferred?

A

Via

  • heating
  • waves
  • an electrical current
  • a force
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9
Q

ENERGY CANNOT BE CREATED…

A

…OR DESTROYED

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10
Q

A closed system is …

A

.. an isolated system where no energy transfers into or out of the systems energy store

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11
Q

What is a gravitational potential energy store?

A

The energy stored in an object because of its position

- eg. Above the ground

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13
Q

What effects kinetic energy in a moving object?

A

Its mass and speed

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14
Q

Wasted energy is …

A

.. energy that is NOT useful

- not in the form and place we want it

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15
Q

What is Wave Power?

A

Energy generated by waves when they turn turbines

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16
Q

What is a Thermal Energy store?

A

The energy a substance has due to its temperature

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17
Q

How can machines be made more efficient?

A

By reducing the energy they waste

- eg. lubrication to reduce friction

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18
Q

Why do machines waste energy?

A

Because of friction, air resistance, electrical resistance and noise

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19
Q

What happens to the energy store when an object falls?

A
  • gravitational potential energy DECREASES

- kinetic energy INCREASES

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20
Q

What is a bio-fuel?

A

Any fuel taken from living or recently living organisms
Eg. Animal waste, ethanol, straw, nutshells, woodchip
They are …
-renewable and carbon-neutral

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22
Q

Where does the wasted energy go?

A

It is transferred to the surroundings which become warmer

23
Q

Everyday electrical appliances include …

A

Heating
Lighting
Making objects move
Producing sound and visual images

24
Q

The thicker the layer of insulation,

A

the lower the rate of energy transfer through it.

25
Q

What are Kinetic Energy stores?

A

The enegy an object has bacause it is moving

26
Q

Electrical appliances can …

A

.. transfer useful energy at the flick of a switch

26
Q

Infrared radiation is emitted and absorbed by …

A

.. all objects

27
Q

The higher the thermal conductivity of a material,

A

the higher the rate of energy transfer through it

28
Q

What are chemical energy stores?

A

The energy transfered during chemical reactions

  • fuels
  • foods
29
Q

The greater the mass of an object …

A

.. the slower its temperature increases when it’s heated

30
Q

The hotter an object is…

A

.. the more infrared radiation it emits in a given time

32
Q

How can the rate of energy transfer from houses be reduced?

A
  • loft insulation
  • cavity wall insultation
  • double-glazed windows
  • aluminium foil behind radiators
  • external walls with thicker bricks and lower thermal conductivity
33
Q

What are the best insulators?

A

Wool and fibreglass

33
Q

The temperature of an object increases if …

A

.. it absorbs more radiation than it emits

35
Q

The specific heat capacity of a substance is …

A

.. the amount of energy needed to change the temperature of 1kg of the substance by 1*

36
Q

What happens to the energy store when an object falls, hits and stays on the ground?

A
  • the kinetic energy DECREASES
  • most or all of the energy is transferred to its surroundings
  • the thermal energy of the surroundings INCREASES
  • energy can be lost through sound
36
Q

What is Nuclear power?

A

Nuclear fuel takes energy from atoms
The nucleus of Uranium is unstable and can split in two. When this happens energy is transferred from the nucleus. All the atoms together become very hot.

37
Q

What is Wind Power?

A

Energy generated from wind turbines

37
Q

What is Hydroelectric Power?

A

Energy generated when rainwater that’s collected in reservoirs flows downhill through turbines

38
Q

What does a Tidal Power station do?

A

It traps water from high tide, which can then be released through turbines. This generates electricity.

40
Q

Fossil fuels produce increased levels of …

A

.. greenhouse gases, which contribute to global warming

41
Q

Most of our energy comes from …

A

.. burning fossil fuels

41
Q

What is Solar Power?

A

Energy from the sun that is absorbed by solar cells that can be used to directly generate electricity.

42
Q

Disadvantages of Renewable energy sources

A
  • not yet able to meet the world demand
  • unreliable
  • expensive to install
  • WIND = loud and unsightly
  • TIDAL = effect river habitats
  • HYDROELECTRIC = habitats flooded to create reservoirs
  • SOLAR = need to cover a large area for lots of energy
43
Q

What is Geothermal Energy?

A

Energy released by radioactive substances deep beneath the earth. The radioactive substances heat surrounding rocks. Stations pump water on them to produce steam which drives the turbines.

44
Q

Advantages of Nuclear Power

A
  • no greenhouse gases

- more energy transferred per kg of uranium than fossil fuels

45
Q

Advantages of Renewable energy sources

A
  • never run out
  • don’t produce greenhouse gases
  • don’t produce radioactive waste
  • cheap to run
46
Q

What is convection and wher does it occur?

A
  • gases and liquid

- when a change in density causes particals to move from HOTTER to COLDER regions

47
Q

Advantages of fossil fuels

A
  • accessible
  • provide a large amount of concentrated energy
  • relatively low cost
48
Q

Disadvantages of fossil fuels

A
  • non-renewable
  • produce co2 when burned
  • release sulfer when burned

Physics (5 decks)

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