Energy Flashcards Preview

Physics > Energy > Flashcards

Flashcards in Energy Deck (86):
0

Types of non stored energy

Kinetic
Light
Sound
Electrical
Thermal

1

Types of stored energy

Nuclear
Chemical
Gravitational potential
Elastic potential

2

Describe kinetic energy

When an object moves

3

Describe light energy

An electromagnetic wave emitted from light sources

4

Describe sound energy

Emitted from anything vibrating

5

Describe electrical energy

Present when current flows

6

Describe Thermal energy

Flows from hot objects to cooler objects

7

Describe gravitational potential energy

Present when an object can fall

8

Describe elastic potential energy

Present when an on object is stretched or compressed

9

Describe chemical energy

Present in foods, batteries and fuels. Released in chemical reactions

10

Describe nuclear energy

Present in the nucleus and released in nuclear reactions

11

The principle of conservation of energy

energy can't be destroyed or created only transferred from one form to another.

12

What is efficiency the measure of?

How much useful energy is produced compared to the total energy input.

13

Efficiency equation

Efficiency =
useful output energy/total input energy ❎100

14

What is the efficiency of a regular light bulb with 200J of electrical energy which produces 10J of light energy?

10/200✖️100 = 5%

15

What increases gravitational potential energy?

More mass
More height
Stronger gravity

16

GPE equation

GPE = mgh

GPE = mass✖️gravity ✖️height

m= GPE/gh
g= GPE/mh
h= GPE/mg

17

What is g on earth?

10N/kg

18

What increases kinetic energy?

More mass
More velocity

19

Kinetic energy equation

KE=1/2✖️mass✖️velocity2⃣

v= ✔️KE/1/2✖️mass

m= 2(KE/v2⃣)

20

What does a pendulum convert?(energy)

GPE>KE

21

Why does a pendulum transfer energy?

Due to the surrounding air resistance

22

What will a pendulum never do unless you push it

Go higher than its initial hight

23

Why will a pendulum never go higher than its original height?

Due to the principal of conservation of energy

24

Equations for work done

Work done= force✖️distance

Work done = energy transferred

25

Power equation

Power(w)= energy transferred(J)/time(s)

26

What is a conductor?

Something which allows heat to flow easily from one end of and object to another

27

Why are solids mostly good conductors?

The particles in a solid are close together, they vibrate, when an object is heated up the particles vibrate more. The particles near the heat vibrate more knocking into neighbours who start vibrating more etc.

28

How are the particles in a solid arranged

In a lattice with a sea of delocalised e- (the e- transfer energy quickly from one place to another).

29

Why is air a good insulator?

It has a low density so energy can't be easily passed between particles.

30

Why is glass a good insulator?

It has no delocalised electrons so heat is slowly conducted.

31

Why is wool a good insulator?

It has no delocalised electrons and has lots of pockets of trapped air which are good insulators.

32

What is convection?

The transfer of hot particles from a hot zone to a cooler zone.

33

Where can convection occur?

In fluids(liquids and gases) but NOT in solids

34

What can't convection occur in solids?

Because the molecules need to be able to one from one place to another.

35

Why do things expand when heated?

In solids because the particles are vibrating more in their fixed positions

In fluid because the particles have more energy and are moving further apart.

36

How do hot air balloons work?

The gas is heated and becomes less dense than the air around it. Because the hot air is less dense it floats on the cooler air around it.

37

How does a radiator heat a room?

The radiation heats air around it
When the air is heated it becomes less dense and rises
Cooler air in room falls
The cycle is called convection current

38

What can thermal radiation also be called

Infrared

39

What is black like for infrared

Good absorber and emitter

40

What is white like for IR

Good reflector
Poor absorber
Bad emitter

41

What is Matt or rough like for IR

Good absorber
Good emitter

42

What is shiny or smooth like for IR

Good reflector
Bad emitter
Poor absorber

43

Describe a vacuum flask.

Cork stopper - prevents conduction
Outer metal/plastic case - protects glass
Vacuum - no particles, stops conduction + convection
Silver lining - prevents radiation

44

Explain heat loss in a house and how to prevent it.

Through roof-loft insulation
Through windows-curtain, double glazing
Though bad fitting doors-draft excluders
Though walls-cavity wall insulation
Lagging hot water tank- padding around

45

When does evaporation occur?

When the most energetic particles in a liquid change from a liquid to a vapour

46

What happens when we sweat?

Heat is transferred from our skin to the sweat
This increases the energy of our sweat molecules
This allows some of the sweat to evaporate
Sweating tales heat energy away from our skin and cools us

47

How can the rate of evaporation be increased?

Increasing the liquids temperature
Decreasing the humidity of the air around the liquid
Increasing the liquids surface area

48

How do plants use evaporation?

They use it to move water from the soil to the leaves

When water evaporates through the stomach, more water is drawn up the xylem vessels from the roots.

49

Nuclear energy transfers

Nuclear>thermal>kinetic>electrical

50

What happens to nuclear energy

Nuclear energy undergoes fission
Water boils, produces steam
Steam turns turbine
Turbine spins generator
Produces electricity

51

Advantages to nuclear energy

Uranium reasonably abundant
Produces lots of power
No co2 emissions

52

Disadvantages to nuclear power

Potential for large scale disaster (meltdown)
Expensive to decommission power station
Mining dangers
Produces long lifetime radioactive waste

53

Coal,gas,oil energy transfers

Chemical>heat> kinetic>electrical

54

What happens to coal

Coal is burnt
Boils water producing steam
Steams turns turbine
Turbine spins generator
Produces electricity

55

Advantages of coals

Coal reasonably abundant
Isn't weather dependant
Reasonably cheap way to produce energy
Well established (advanced)
Produces lots of energy

56

Disadvantages of coal

Produces co2>greenhouse effect>climate change
Can produce sulphur dioxide> acid rain
Fossil fuel will eventually run out

57

Wood burning transfers

Chemical>thermal>kinetic

58

Advantages of wood burning

despite co2 given out it's taken in photosynthesis
Wood is Renewable
Woods are nice

59

Disadvantages to woodburning

Needs lots of space
Produces less power than coal

60

Hydroelectric power transfers

GPE>kinetic>electrical

61

Hydroelectricity advantages

Produces large amounts of power and is reliable
Minimal running costs
No co2 emissions
Renewable

62

Hydroelectricity disadvantages

Floods large area> displaces people and animals
Very high initial costs
Van only build in certain areas

63

Wind power energy transfers

Kinetic>electrical

64

Advantages of wind power

Renewable
Minimal running costs
No fuel used or emissions
Cam use space around turbines still

65

Disadvantages to wind power

Spoil view
Not very efficient
Needs lots to replace traditional power stations
No wind means no electricity

66

Solar cell energy transfers

Light>electrical

67

Solar panel energy transfers

Thermal>thermal

68

How do solar cells work?

Light causes current to flow in the solar cells

69

How do solar panels work

Suns thermal energy is used to heat water

70

Advantages to solar energy

Minimal maintenance
Small cells are cheap and good for running small devices

71

Disadvantages of solar energy

Only works when sunny
Productions process uses lots or energy and material
Not suitable for large scale energy production (large area needed)

72

Geothermal energy transfers

Thermal>kinetic>electrical

73

How geothermal energy works

Cold water is pumped down to hot rocks which boils the water
Steam comes back up and spins a turbine
Turbine spins generator making electricity

74

Advantages of geothermal energy

No co2 emissions
Minimal maintenance or running costs
Can use the waste hot air to heat places

75

Disadvantages of geothermal energy

Very few places where thin crust is available
Hard to drill down several km to hot rocks

76

Tidal barrages energy transfers

(GPE>)Kinetic>electrical

77

How tidal barrages work

Barrage built across inlet
When tide goes in water spins turbines
Turbines spins generator
Also happens when tide goes out

78

Advantages of tidal barrages

No emissions
Low running costs
Predictable
Acts as bridge

79

Disadvantages of tidal barrage

Distrusts wildlife
Can only be built in certain areas (with big change in tide levels)
Disrupts boats
High initial costs to build

80

Wave power energy transfers

Kinetic>electrical

81

How does wave power work?

Either
Waves make flaring blocks move
Or a wave is forced into a narrow gap, this pushes air though a turbine...

82

Advantages of wave power

Good for remote (coastal) regions
No fuel means no emissions
Minimal running costs

83

Disadvantages if wave power

Spoil beach or mess with shipping
Not suitable for large scale generation
Weather dependent

84

Other biomass energy transfers

Chemical>thermal>kinetic>electrical

85

Other biomass works by...

Using waste materials to produce fuels to burn via a myriad of techniques