Energy Flashcards

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1
Q

All the units used for energy

A

kilogram (kg), joule (J), metre (m), metre/second (m/s),
metre/second2 (m/s2), newton (N), second (s) and watt (W)

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2
Q

Energy Stores

A

energy stores: chemical, kinetic, gravitational, elastic, thermal, magnetic,
electrostatic, nuclear

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3
Q

Energu transfers

A

energy transfers: mechanically, electrically, by heating, by radiation
(light and sound)

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4
Q

What does the prinicple of energy state

A

In any process energy is never created or destroyed. (It is just transferred from one store to another.)

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5
Q

Equation for efficiency

A

(total energy output / useful energy output) x 100%

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6
Q

What is condution

A

Conduction is the transfer of thermal energy through a substance by the vibration of the atoms within the substance. Metals are good conductors because they have free electrons that can move easily through the metal, making the transfer of energy happen faster.

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7
Q

What is convection

A

Convection occurs in a liquid or gas. These expand when heated because the particles move faster and take up more volume – the particles remain the same size but become further apart. The hot liquid or gas is less dense, so it rises into colder areas. The denser, colder liquid or gas falls into the warm areas. In this way, convection currents are set up which transfer heat from place to place.

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8
Q

What is thermal radiation

A

Thermal radiation is the transfer of energy by infrared (IR) waves. These travel very quickly in straight lines.

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9
Q

Where is convection used?

A

Hot air balloon

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10
Q

What surface absorbs light the most, but reflects the least?

A

Dark surfaces

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11
Q

What surface absorbs light the least, but reflects the most?

A

Light (shiny) surfaces

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12
Q

How can we reduce insulation?

A

There are some simple ways to reduce this loss, including fitting carpets, curtains and draught excluders. Energy loss through windows can be reduced using double glazing. These kind of windows have air or a vacuum between the two panes of glass.

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13
Q

Equation for work done

A

Work done = force x distance moved

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14
Q

Law of work:

A

Whenever a force makes something move, work is done. The amount of work done is equal to the amount of energy transferred. Bonus: it is measured in Joules

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15
Q

Equation for gravitational potential energy (GPE)

A

mass x gravitational field strength (10 in Earth) x height

(m x g x h)

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16
Q

Equation for kinetic energy

A

1/2 x mass x speed2(squared)

17
Q

how conservation of energy produces a link between GPE, kinetic energy and work

A

Because energy is conserved the decrease in GPE = increase in KE, for a falling object if no energy is lost to the surroundings

18
Q

What is power?

A

Power is the rate of transfer of energy between energy stores. One watt (W) is equal to one joule per second (J/s).

19
Q

Equation for power:

A

power = work done / time taken

20
Q

State energy resources (7)

A
  • Wind
  • Solar
  • Nuclear
  • Fossil Fuels
  • Water
  • Geothermal resources
  • Solar heating systems