Physics3 8K Energy Transfers Flashcards

1
Q

The sun’s heat energy that travels across space to warm Earth is called……

A

……..infra-red (or IR)

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2
Q

Are dark or light colours the best good emitters and absorbers of radiation

A

Dark

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3
Q

What does a Sankey diagram show?

A

A Sankey diagram shows the energy transfers. The width of each arrow shows the amount of energy it represents.

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4
Q
Which of these is not a way of trying to
reduce energy bills?
A increasing the insulation in your home
B using more efficient appliances
C using appliances with high power ratings
D using solar power to heat water
A

C using appliances with high power ratings

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5
Q

What does emit mean?

A

To give out.

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6
Q

What does thermal insulator mean?

A

A material that does not allow internal (thermal) energy to be transferred through it easily.

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7
Q
Which list of materials shows only
insulating materials?
A wool, feathers, copper
B feathers, wood, carpets
C iron, copper, steel
D plastic, aluminium foil, wood
A

B feathers, wood, carpets

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8
Q

What does absorb mean?

A

‘To soak up’ or ‘to take in’.

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9
Q

What happens to the energy in a cup of iced tea left in a cold kitchen?

A

It will increase as the iced tea gains energy from the air in the kitchen until they are both at the same temperature.

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10
Q

Temperature is measured in,,,,,,

A

One of
degrees Celsius (°C).
Fahrenheit (F)
Kelvin (K)

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11
Q

What is a fossil fuel?

A

A fuel formed from the dead remains of organisms over millions of years (e.g. coal, oil or natural gas).

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12
Q

What units for energy are used on

electricity bills?

A

kilowatt-hours

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13
Q

What does evaporate mean?

A

When a liquid turns into a gas.

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14
Q

The efficiency of an appliance is calculated

by…….

A

…….comparing the useful energy

transferred to the total energy supplied

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15
Q

What happens to the energy in a hot cup of tea left in a cold kitchen?

A

It leaves the tea until it is a the same temperature as the air in the room

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16
Q

How does sweating work?

A

Sweating cools us down when the sweat evaporates and takes some heat energy with it.

17
Q

What happens to the particles in evaporation?

A

When some of a liquid evaporates, it is the particles moving the fastest that escape and form a gas.

18
Q

What are the units for measuring power?

A

Watts (W) or kilowatts (kW)

19
Q

Which word describes the way energy is transferred through solids by heating?

A

Conduction

20
Q

Which type of surface would reflect
infrared radiation the best?
A white and dull B black and shiny
C white and shiny D grey and dull

A

C white and shiny

21
Q

What does efficiency mean?

A

How much energy something wastes.

22
Q

Why does the cold air near an ice lolly move downwards?

A

It is colder and denser than the air further away from it.

23
Q

The amount of thermal energy in an object depends on what three things?

A

Its mass, its temperature, the material it is made from.

24
Q

How do you calculate payback time?

A

Payback

time = cost of change/savings per year

25
Q

What is the unit for measuring energy.

A

a Joule (J)

26
Q

What does thermal conductor mean?

A

A material that allows internal (thermal) energy to be transferred through it easily.

27
Q

How can you find the power of an

appliance?

A

Look for the power rating on the label

28
Q

Why do many insulating materials contain

trapped air?

A

1) gases are poor conductors and

2) gases cannot transfer energy by convection if they cannot move.

29
Q

Why are solids are better heat conductors than liquids or gases?

A

The particles are closer together in solids.

30
Q

What is climate change?

A

Changes that will happen to the weather as a result of global warming/ the rlease of greenhouse gases (e.g carbon dioxide and methane).

31
Q

When one end of a piece of metal is heated the particles vibrate ….

A

……… more and the vibrations are passed from particle to particle.

32
Q

What does reflect mean?

A

To bounce off a surface

33
Q

What does ‘payback time’ mean?

A

The time it takes to save enough money

on energy bills to pay for a change

34
Q

The rate at which energy is transferred is called

A

Power

35
Q

Which word describes the way energy is transferred by heating in fluids?

A

Convection