P1- Energy Flashcards
1
Q
What is energy transferred by?
A
Energy stores
2
Q
What are the eight energy stores?
A
Thermal energy stores Chemical energy stores
Kinetic energy stores Magnetic energy stores
Gravitational potential energy stores Electrostatic energy stores
Elastic potential energy stores Nuclear energy stores
3
Q
What is it meant by system?
A
Single object or a group of objects
4
Q
What happens when a system changes?
A
Energy is transfered
5
Q
What are closed systems?
A
Systems where neither matter nor energy can enter or leave.
6
Q
What is the net change in a closed system?
A
Zero
7
Q
What is meant by work done?
A
Energy transferred
8
Q
What is the initial force exerted by a person throwing a ball upwards?
A
Chemical
9
Q
What is a ball dropped from a height accelerated by?
A
Gravity
10
Q
What energy does a moving object have?
A
Kinetic energy
11
Q
What two things does kinetic energy store depend on?
A
Mass & speed
12
Q
What is the equation for kinetic energy?
A
E (j) =1/2 x mass(kg) x velocity^2 (m/s)
13
Q
What does movement mean?
A
Energy in an object’s kinetic energy store
14
Q
If something is moving what energy store does it have?
A
Kinetic energy
15
Q
What changes the amount of kinetic an object has?
A
Mass and speed
16
Q
How does the mass of an object change its speed?
A
The greater the mass the greater the speed
17
Q
What is the formula for kinetic energy?
A
e=1/2mass x velocity(speed)^2
18
Q
What energy store does a raised object have?
A
Gravitational potential
19
Q
What does lifting an object in a gravitational field require?
A
Work
20
Q
How does the height of an object change the gravitational potential energy?
A
The higher the object the more gravitational potential energy
21
Q
What impacts an object in a g.p.e energy store?
A
- Mass
- Height
- strength of the gravitational field the object is in
22
Q
Do falling objects also transfer energy?
A
Yes
23
Q
When an object is falling what is the energy transfers?
A
Gravitational potential energy store is transferred to its kinetic energy store
24
Q
In real life do all falling objects have air resistance?
A
Yes
25
(For a falling object where there is no air resistance) Energy lost from the g.p.e store=?
Energy gained in the kinetic energy store
26
What can stretching transfer the energy into?
Elastic potential energy stores
27
What can stretching or squashing transfer energy into?
Elastic potential energy
28
Elastic potential(j) =
1/2 spring constant (N/m)x extension^2(m)
29
Do all materials have the same specific heat capacities?
No
30
If a material needs lots of energy to gain heat does it mean it also transfers lots of energy to cool down?
Yes
31
Define specific heat capacity?
The amount of energy required to raise the temperature of 1kg by 1 degree celsius
32
What is the equation for specific heat capacity?
Change in thermal energy (j)= mass(kg) x specific heat capacity(j/kg degrees celcius)
33
What equipment do you need to investigate specific heat capacity?
- A solid material(e.g copper) with two holes in it
- Heater
- Thermometer
- Ammeter
- Power supply
34
Can energy be destroyed?
No
35
What is the conservation of energy principle?
Energy can be transferred usefully, stored or dissipated, but can never be destroyed
36
When energy is transferred between stores is all of the energy transferred usefully?
No
37
What is the word used to describe what happens to energy that isn't transferred usefully?
Dissipated/ waste energy
38
Is a mobile phone a system?
Yes
39
When you use a phone how is energy usefully transferred into battery?
Chemical energy
40
What is an example of dissipated energy in a mobile phone?
Thermal energy
41
What is a closed system?
A type of thermodynamic system where mass is conserved within the boundaries of the system, but energy is allowed to freely enter or exit the system.
42
What is power 'the rate of'
'Rate of doing work'/'Rate of energy transfer'
43
What is power measured in?
Watts
44
One watt=
1 joule of energy transferred per second
45
Powe (w)=
Energy transferred(j)/time(s) or work done(j)/time(s)
46
Where does conduction occur?
In solids
47
What is conduction the process of?
Vibrating particles transfer energy to neighbouring particles
48
If something is transferred to an object by heating what store does it go to?
Thermal wich is shared across the kinetic energy stores of the particles in the object
49
Do the particles in an object that is being heated vibrate more and collide with each other?
Yes
50
What energy do colliding particles cause to be transferred between each other?
Kinetic
51
Where does convection occur?
Liquids and gases
52
What happens in convection?
Energetic particles move away from hotter to colder regions
53
How is energy transferred in convection?
By heating to the thermal store of the liquid or gas. The energy is shared across the kinetic energy stores of the liquid or gas particles
54
Are the particles in solids able to move?
No
55
Are the particles in liquids able to move?
Yes
56
Are the particles in gasses able to move?
Yes
57
What happens to the particles in a region that are heated up in a liquid?
They move faster
58
What happens to the gaps in between the particles
| when a liquid or solid is heated?
They increase
59
Does the density of a gas or liquid increase when it is heated?
No
60
Radiators create convection..?
Currents
61
How is energy transferred from a radiator to nearby air particles?
Conduction
62
Where does warm air go?
Up
63
What are ways u can reduce the amount of energy scampering off to a completely useless store?
Lubricant and thermal insulators
64
What does lubricant do?
Reduce frictional force
65
Whenever something moves how many fictional forces act against it?
At least one
66
What do insulators reduce the rate of?
Energy transferred by heat
67
What are things you can do to reduce the amount of energy that escapes the house?
-Have thick walls. The thicker the walls are the lower their thermal conductivity the slower the rate of energy transfer( so the building will cool more slowly
- Cavity walls which have an inner and outer walls which have a gap in between
- Loft insulation
- Double-glazing windows
- Draught excluders around doors and windows reduce energy transfers by convection
68
Do most energy transfers involve some waste energy?
Yes
69
What is the main useless energy store?
Thermal energy
70
The less energy wasted what is the product?
More efficient
71
How can you improve the efficiency of an object?
- Insulating
- Lubricating
- Streamline
72
What is the equation for efficiency?=
Useful output energy/Total input energy transfer or useful power output/total power output
73
Is any device 100% efficient?
No (apart from electric heaters because all the energy is transferred into useful thermal energy stores
74
What are energy stores (renewable and non-renewable) generated to make?
Electricity
75
What are the three main fossil fuels?
- Coal
- Oil
- (natural) Gas
76
What are 7 renewable resources?
- Wind
- Water waves Hydro-electricity
- The sun (solar)
- Bio-fuel
- Tides
- Geothermal
77
Do most renewable reasources damage the environment?
Yes but it is less nasty then non-renewable ways
78
What are non-renewable energy resources for transport?
- Petrol and diesel use fuel created by from oil
| - Coal
79
What are renewable energy resources for transport?
Bio-fuels
80
What are non-renewable energy resources for heating?
- Natural gas
- Coal
- Electric heaters
81
What are non-renewable energy resources for heating?
- Geothermal
- Solar water heaters
- Bio-fuel
82
Where are turbines often placed?
Moors or around coasts
83
Where does the pollution come from in wind turbines?
When the are being manufactured
84
How many turbines do you need to replace 1 coal fire?
1500, which spoils scenery
85
What are cons of wind power?
- Spoils views
- You need a lot of wind power for the same amount of energy as non-renewable resources
- It isn't always wind ( they only produce energy 70-85% of the time)
- The initial cost is high
86
What are pros of wind power?
- It is renewable
- There are no fuel costs and minimal running costs
- There's no permanent damage to the landscape
87
What are pros to solar power?
- They are often the best option to be used in calculators and watches which don't use much energy
- There's no pollution
- In sunny countries it is a very reliable source
- Once it has started running the cost is basically nothing
- They can also be used in cloudy countries
88
What are cons of solar power?
- They only run at day time
- You can't increase the energy output for extra demand
- The initial costs are high
89
Where is geothermal energy available?
In volcanic areas or where hot rocks lie near the surface?
90
Does geothermal energy damage the environment?
No very much
91
What is the main drawback of geothermal energy?
there aren't many sustainable locations for power plants, and that the cost of building a power plant is often high compared to the amount of energy it produces
92
What kind of water does hydroelectric power use?
Falling
93
What does hydroelectric power use, flooding...
Valley by building or big damn
94
Is there any pollution with hydroelectric power?
No
95
What is a negative impact that hydroelectric power has on the environment?
- Due to the flooding of the valley rooting vegetation releases methane and C02.
- Possible loss of habitat
96
How fast can hydroelectric power respond to increased demand?
Almost immediately
97
Are the initial costs high for hydroelectric power?
Yes
98
Are there any fuel costs to hydroelectric power?
No
99
Are the running costs high for hydroelectric power?
No
100
Is hydroelectric power good for big areas?
No
101
What is wave power?
Lots of little wave-powered turbines
102
Where are lots of little wave-powered turbines located?
By the coast
103
What are cons to wave power?
- Disrupting seabeds and habitats
- Spoiling the view
- Hazard to boats
- They are a bit unreliable
- Initial costs are high
- Can't provide energy on a large scale
104
What are pros to wave power?
-It can be very useful
-No pollution
-
105
What are tidal barrages?
Big dams built across river estuaries, with turbines in them. As the tide comes in it fills up the estuary. The water is then allowed out through turbines at a controlled speed?
106
How are the tides produced in wave power?
The gravitational pull of the Sun and Moon
107
What are the main problems of tidal barrages?
Preventing free access by boats, spoiling the view and altering the habitat of wildlife
108
Are thwle tides reliable for energy?
Yes
109
Can the height of the tide variable?
Yes, this is a drawback because lower (neap) tides will provide significantly less energy than bigger 'spring' tides.
110
What are additional costs to tidal barrages?
Minimal running costs
111
Are the initial costs high of tidal barrages?
Yes
112
Are there fuel costs with tidal barrages?
Yes
113
What are brio-fuels made from?
Plants and waste
114
Are bio-fuels renewable?
Yes
115
Are bio-fuels carbon neutral?
Yes
116
Are bio-fuels reliable?
Yes
117
Can bio-fuels respond to immediate demands?
No
118
Is there a cost to refine bio-fuels?
Yes, it 's high
119
Do bio-fuels produce CO2?
Yes
120
Can bio-fuels cause a loss of habitat?
Yes
121
Are fossil fuels reliable?
Yes
122
Is nuclear energy reliable?
Yes
123
Is running a nuclear power plant expensive?
No
124
Is the cost of setting up a nuclear power plant expensive?
Yes
125
Is extracting nuclear energy expensive?
No
126
What are 7 disadvantages of non-renewable energy?
1. Coal, oil and gas release CO2 into the atmosphere when they're burned. This creates the greenhouse gas effect
2. Burning coal and oil causes realeses sulfur dioxide, which causes acid rain- which can be harmful to trees and soils and can have far-reaching effects in ecosystems
3. Coal mining makes a mess of the land scale, especially "open cast mining". As with many energy resources, the view can be spoilt by fossil fuel power plants
4. Oil spillages cays serious environmental problems, affecting mammals and birds that live in and around the sea
5. Nuclear power is clean but the nucleur waste is very dangerous and difficult to dispose of
6. Nuclear fuel is cheap but the overall cost of nuclear power is high
7. Nuclear power always carries the risk of a major catastophe
127
Where is most of our energy from?
Fossil fuels and nuclear energy
128
Why are energy providers to use renewable energy sources?
Fossil fuels are more cost efficient
129
Describe the energy transfers that occur when a liquid is heated using equipment
The current flowing throughthe immersion heaterdoes work The current flowing through the immersion heater does work, transferring energy electrically to the thermal energy store of the immersion heater. It is then transferred from the thermal energy of the immersion heater to the thermal energy store of the liqued
130
Define wasted energy
Energy transferred to a less useful energy store
131
State the units for Specific Heat
| Capacity.
J/°C/kg
| Joules/Degree Celsius/Kilogram
132
What is the definition of ‘Power’?
The rate at which energy is transferred
| or rate at which work is done
133
State two equations for power. Give SI units for all
| quantities involved.
ower = energy transferred/time
power = work done/time
Energy (J), Work Done (J), Time (s)
134
What is the unit of power?
Watt (W)
135
Two motors lift the same mass through
the same height. Motor A does this in
half the time of Motor B. Which
dissipates the most power?
Motor A.
The energy transferred is the same but
the time taken is less (P=E/t).
136
Describe the energy changes involved when a ball is
thrown upwards and then returns to its starting
position. Ignore air resistance.
● Upwards: KE is converted to GPE
● Peak: Maximum GPE, zero KE
● Downwards: GPE is converted to KE
KE (Kinetic Energy), GPE (Gravitational Potential Energy)
137
Describe the energy transfers for a bungee jumper.
● When falling, the GPE is converted to KE of
jumper
● As the cord tightens, KE is converted and
stored as Elastic Potential Energy (EPE)
● At lowest point, the jumper’s initial GPE
equals the EPE stored in the cord
138
Explain why a bungee jumper slows down once the
| cord begins to stretch.
● Kinetic energy decreases since it is
converted to elastic potential energy
● Since KE is proportional to (velocity)²,
as KE decreases, so does velocity.
139
Give examples of chemical energy stores.
● Food
● Fuel (eg. wood, coal, petrol)
● Batteries
140
State 4 different stores of energy.
1. Kinetic Energy
2. Gravitational Potential Energy
3. Elastic Potential Energy
4. Chemical Energy
141
State the law of energy conservation.
Energy cannot be created or destroyed
(it can only be transferred into different
forms).
142
State any changes in the total energy of
a ball that is kicked, assuming that no
external forces act.
The total energy of the system remains
constant due to the conservation of
energy
143
What is waste energy?
The energy that is not used by the device
| for its desired purpose.
144
Describe the energy changes that occur
| in a filament light-bulb.
● Electrical energy is transferred into
light and heat energy
● Light is a useful energy form, heat is
waste energy
145
State two equations to calculate
| efficiency.
=Useful Output Energy Transfer/Total
Input Energy Transfer
=Useful Power Output/Total Power
Output
146
How can the efficiency of a system be
| increased?
1. Reducing waste output (by
lubrication, thermal insulation etc.)
2. Recycling waste output (eg. recycling
thermal waste energy as input energy)
147
State the consequence for energy transfer of a
| material with a igh thermal conductivity.
The rate of energy transfer through the
material is higher than for a material with
a lower thermal conductivity
148
Do double-glazed windows have a higher or lower
| thermal conductivity than single-glazed windows?
Lower, meaning less energy transfers
| through them.
149
What key factors affect the rate of cooling of a
| building?
● The thickness of the walls
| ● The thermal conductivity of the walls
150
State three methods of reducing heat
| loss in a building.
1. Double glazing
2. Loft and wall insulation
3. Thicker walls
151
How can the efficiency of a mechanical machine with
| moving parts be improved?
Lubricate any moving parts to reduce the
friction and therefore energy loss due to
heating.
152
How can the efficiency of a radiator be
| improved?
Installing metal foil sheets behind the
radiator to reflect the heat back into the
room rather than it being absorbed into
the walls.
153
How can the efficiency of boiling water in
| a pan be improved?
By placing a lid on the pan to reduce the
| heat loss from the top.
154
What is a renewable energy resource?
An energy source which can be
| replenished as it is being used up.
155
Give four examples of renewable energy
| resources.
1. Wind Energy
2. Hydro-Electricity
3. Tidal Energy
4. Solar Energy
156
Give an example of a non-renewable
| energy resource.
```
Fossil fuels (for example coal, oil and
gas).
```
157
What are the advantages of generating power using
| gas rather than coal?
● Flexible Generation: Gas power
stations have short start-up times so
can be switched on/off more readily
● Lower emissions of carbon dioxide
158
State two disadvantages of using
renewable energy resources to generate
power.
● Output often determined by external factors
(like wind speed), so supply is uncertain
● Generating power through other means is
often more efficient and economically
beneficial
159
Explain the environmental impacts of burning fossil
| fuels.
```
● Carbon Dioxide contributes to the
greenhouse effect, and causes global
warming
● Sulphur Dioxide leads to acid rain, which
can damage buildings and crops
```
160
State three advantages of fossil fuels as an energy
| resource.
1. Reliable: Not dependent on external factors
so can generate power anytime
2. Can produce large amounts of energy for a
given quantity
3. Still relatively abundant, so cost-effective
161
State three advantages of nuclear
| power.
1. Very large amounts of energy for relatively
small quantities of fuel
2. Doesn’t release greenhouse gases and so
doesn’t contribute to climate change
3. Low fuel costs
162
State three disadvantages of nuclear
| power.
1. Produces nuclear waste which is harmful to
humans & must be safely stored for centuries.
2. Non-Renewable energy source
3. Risk of nuclear accidents, which have fatal
consequences on humans and the
environment
163
How does hydroelectric power produce
| energy?
```
● Rainwater collects behind a dam
● When this water is released, it is used
to turn a turbine
● This turbine turns a generator which
produces electricity
```
164
What are some disadvantages of using biofuels?
● When plants are burned or decay they release CO2
● In order to grow biofuels, you need to destroy land
which leads to problems because:
○ The land could have been natural habitats
○ Destroying land may involve burning plants growing
on it, which would release CO2
● Growing biofuels reduces the land available for growing
food
165
What are the advantages of tidal energy
| sources?
```
● They do not produce greenhouse gases
● They are quite reliable, as tides happen
twice a day
● They are cheap to run as tides are
natural, and so are free
```
166
What are the disadvantages of
| hydroelectric power?
● The dam may cause flooding
● It can cost a lot to install the required
infrastructure
167
What are some advantages of solar panels?
```
● They don’t cause harm to the
environment
● They are a renewable resource
● They can be used in remote areas where
other types of energy are less accessible
```
168
Give an example of a social factor which may act as
| a deterrent for certain types of energy production.
● Visual Pollution
● Sound Pollution
(both of these are disadvantages of wind farms)
