Energy Flashcards

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1
Q

What is energy measured in?

A

Energy is measured in joules.

There is energy in the chemical stores associated with food and fuel.

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2
Q

What is the law of conservation of energy?

A

Energy cannot be created or destroyed only transferred.

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3
Q

Chemical energy

A

Food, fuel, batteries

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4
Q

Thermal

A

Hot objects

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5
Q

Kinetic energy

A

Moving objects

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6
Q

Gravitational potential

A

Position in a gravitational field

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7
Q

Elastic

A

Changing shape, stretching or squashing.

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8
Q

How can energy be transferred?

A

Electric current, light and sound are ways of transferring energy.

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9
Q

What is dissipation?

A

Dissipation is a term that it is often used to describe ways in which energy is wasted.

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10
Q

Temperature

A
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11
Q

An example how energy and temperature are different

A

You can have a swimming pool and beaker of water at exactly the same temp. The swimming pool represents a much bigger thermal store of energy than the beaker.

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12
Q

The energy needed to increase the temp of a material depends on?

A

The mass of the material
What the material is made of
The temperature rise you want.

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13
Q

What happens with energy between hot and cold objects?

A

Energy is transferred from the hot object to the colder one.
Energy will be transferred and the temperature difference will decrease, until the objects are in equilibrium.

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14
Q

How is energy transferred in solids?

A

It is transferred by conduction.
In conduction, particles transfer energy by colliding with other particles when they vibrate.
Energy transfer happens until the two surfaces are at the same temp.

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15
Q

What is an insulator?

A

An insulator is a poor conductor.

Wood and many non- metals transfer energy v slowly through them.

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16
Q

Convection

A

Energy is transferred by convection in liquids and gases.

Heat energy is transferred from hot places to cooler places

17
Q

Radiation

A

Energy is transferred by radiation which does not need a medium to travel through.
All objects emit radiation.Travels as waves.

18
Q

Infrared radiation can be detected by….

A

Your skin and a thermal imaging camera. It absorbs infared and produces an image.

19
Q

What are fossil fuels?

A

Coal, oil and gas are energy resources and are non-renewable.
They can be used to drive a generator in a thermal power station.
They produce a lot of carbon dioxide which is a greenhouse gas.
Also produces pollutants such as sulfur dioxide and nitrogen oxides.

20
Q

How is electricity generated in a power station?

A

A fuel burns to heat water and produce steam. The steam drives a turbine, the turbine drives a generator which provides the push that means a current flows in a kettle.

21
Q

What are renewable resources?

A

They will not run out.

Wind, tidal, biomass, solar, hydroelectric and geothermal.

22
Q

Hiw can you calculate power?

A

Power (W) = energy (j) / time (s)

23
Q

How can you calculate work?

A

Work done (J) = force (n) x distance (m)