Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

(A) Physics > P7 > Flashcards

P7 Flashcards

1
Q

What is chemical energy

A

Energy stored in the bonds of compounds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is thermal energy

A

Energy relating to temperature, or a change in temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is kinetic energy

A

Energy an object has due to motion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is graviational energy

A

The energy an object has due to gravity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is elastic energy

A

The mechanical potential energy of a material as work is performed on it

(Energy associated with deforming metals)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is nuclear energy

A

Energy associated with nuclear fusion or fission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is electrostatic energy

A

Energy associated with the distortion of electric fields and charges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What i magnetic energy

A

Energy associated with the separation or joining if magnetic poles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is non-zero speed

A

The speed of any object with kinetic energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How is GPE calculated

A

Mass × gravity × height

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How is kinetic energy calculated

A

1/2mv²

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How is thermal energy calculated

A

Mass × SHC × ∆temp

SHC is the energy needed to increase an object by 1°C or 1K

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How is elastic energy calculated

A

1/2kx²

K= spring constant
X = extension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How is energy transferred

A

Mechanically → using forces
Electrically → using current
Heating by particles
Heating by radiation
.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

In what way is kinetic energy transferred

A

Mechanically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How is efficiency of energy transferr calculated

A

(Input energy ÷ output energy)×100

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How are thermal and chemical energy transferred

A

By heating of particles

Chemical energy can also be transferred mechanically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How do electromagnetic waves transfer energy

A

Heating by radiation
The greater their frequency, the greater their energy transfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe the changes in energy when falling down a steep slope

A

Gravitational energy is transferred mechanically to kinetic energy

Then mechanical again kinetic energy is transferred to chemical energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the conservation of energy

A

Energy cannot be created or destroyed
Energy can only be transferred between stores

21
Q

What happens during the transfer of energy in a closed system

A

The increase of energy in one store will be equal to the decrease in another store

22
Q

Where does an electric current transfer energy from

A

From a chemical store in a battery
From a chemical or nuclear store, used to power the mains elesctricity

23
Q

What are power ratings

A

Ratings given to appliances to show how much energy they will transfer faster

24
Q

Whats an advantage to using high energy rated appliances

A

They will complete a task faster, but at a higher price

25
Q

How do you calculate electrical work done

A

Work done = power × time

26
Q

What is electrical work done measured in

A

kWh (killowatt hour)

27
Q

How do you transfer joules to kWh

A

1kWh = 3.6×10⁶ J

1kW = 1000J
Hour = 3600s

28
Q

How do you calculate the cost of an appliance

A

Electrical work done × current rate

29
Q

What do electrical appliances do (energy transfer)

A

Transfer energy electrically from chemical stores

30
Q

How is energy transferred when current flows through a wire

A

When current flows through a wire the wire heats up
This means energy is transferred to a chemical store and is wasted

31
Q

Why cant appliances such as motors be 100% efficient

A

As energy is transferred to the thermal store

32
Q

In what systems is chemical energy lost to the surroundings

A

In all mechanical systems

33
Q

Why is electricity transferred at a high voltage but low current

A

To reduce the heat loss to the environment
(Through heating of particles)

34
Q

What is energy diserpation

A

Loss of energy to the surroundings

35
Q

How is energy loss reduced in mechanical systems

A

Using lubrication reduces friction, and therefore energy loss is reduced

36
Q

How is heat loss by heating of particles reduced

A

By using insulation
(Insulating materials)

37
Q

What is thermal conductivity

A

A measure of how quickly energy is transferred through a material

The thermal conductivity of a material is fixed and doesnt change based on its mass

The higher the thermal conductivity the faster energy is transferred

38
Q

Why are houses built using materials with a low thermal condictivity

A

Prevents hot air entering and making the house hot during summer
Prevents hot air leaving the house during winter

It reduces the transfer of heat to the surroundings

39
Q

What is a cavity wall

A

A method of insulating a building

Insulating material (low thermal conductivity) is placed between the inner and outer walls of a house

40
Q

How does loft insulation help reduce heat loss

A

As hot air rises it is important to have good loft insulation

This will reduce the heat loss to the surroundings

41
Q

How does double glazing reduced a houses thermal conductivity

A

As that is placed between the panes of glass has a low thermal conductivity

Glass also has a relatively low thermal conductivity

42
Q

How does increasing the thickness of a wall affect energy transfer

A

The thicker the wall the slower the transfer of energy

Heat is transferred by conduction at a slower rate
There is a greater distance the energy has to be moved

43
Q

What is conduction

A

Energy transferred between neighbouring atoms or molecules

44
Q

Why are igloos warm

A

Although ice is a ‘cold’ material, they have a low thermal conductivity, and therefore can trap heat inside

45
Q

How do you calculate the efficiency of energy transfer

A

Efficiency = (useful output energy ÷ input energy) × 100

46
Q

What is a sankey diagram

A

A diagram drawn showing total energy, and how much is wasted or useful

The size of an arrow represents the amount of energy transferred

47
Q

How are sankey diagrams drawn

A

You need to use a scale so that the size of the arrow is proportional to the energy

48
Q

How do you improve efficiency

A

Use insulation.
Use materials that reduce unwanted energy transfer
Use technology to produce better devices, e.g LEDs which give of little heat

(A) Physics (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions