Unit 4 Energy Resources and Energy Transfers

Question 1

What is the principal of conservation of energy?

Answer 1

Energy is neither created nor destroyed. But can transform from one type to another.

Question 2

What is the formula for work done?

Answer 2

force x distance = work done
W = F x d

Question 3

What is work done equal to?

Answer 3

Work done is equal to the amount of energy transferred

Question 4

What is the formula for gravitational potential energy?

Answer 4

GPE = m x g x h

gravitational potential energy = mass x gravitational field strength x height

Question 5

What is the formula for Kinetic Energy?

Answer 5

KE = 1/2mv^2
kinetic energy = 1/2 x mass x volume^2

Question 6

What is the link between kinetic energy, gravitational potential energy and work done?

Answer 6

All three of these properties are interconnected because they follow the law of conservation. For example, as an object falls the gravitational potential energy turns into kinetic energy. In which the work done is equal to the change in energy.

Question 7

What is the formula for power?

Answer 7

power = work done/time taken

Question 8

What is power?

Answer 8

Power is a measure of how quickly energy is transferred from one form to another/work done in a certain period of time.

Question 9

What is work done?

Answer 9

Work done is the product of a force applied and the distance that the force moves the object to.

Question 10

What are the two ways of energy?

Answer 10

Energy transfers + Energy Stores

Question 11

What are the energy stores?

Answer 11

Types of energies:

chemical, kinetic, gravitational, elastic, thermal, magnetic, electrostatic, nuclear

Question 12

What are the energy transfers?

Answer 12

Ways that energy can be turned into another store:

mechanically, electrically, by heating, by radiation (light and sound)

Question 13

What is the formula for efficiency?

Answer 13

useful energy output/total energy output x 100% = efficiency

Question 14

What is efficiency?

Answer 14

how effective an energy system converts the input energy into useful output energy.

Question 15

What is useful energy output?

Answer 15

the type of energy actually needed to perform the work.

Question 16

What is total energy output?

Answer 16

all of the different types of energy output from the system. including both useful and waste.

Question 17

What are the typical forms of waste energy?

Answer 17

heat and sound

Question 18

How does thermal energy transfer occur?

Answer 18

conduction, convection and radiation

Question 19

What is conduction?

Answer 19

the transfer of thermal energy through direct contact. in solids the heat is transferred from high temperature to low. as they vibrate and collide with neighboring particles.

Question 20

What are good conductors and bad?

Answer 20

metals are good conductors of heat due to the free movement of electrons. while non-metals aren’t so great.

Question 21

What is convection?

Answer 21

the transfer of thermal energy through movement of fluid (liquids and gases). warmer regions of fluid become less dense and rise while cooler regions become more dense and sink. this makes a convection current.

Question 22

What is a convection current?

Answer 22

a circulation pattern of particles during convection. particles that get hot rise up, they then become cold again and sink down. the heat source is at the bottom so they become hot again and repeat the cycle.

Question 23

What are some examples of convection used in everyday phenomena?

Answer 23

weather systems, ocean currents and heating/cooling systems.

Question 24

What is radiation?

Answer 24

transfer of thermal energy through electromagnetic waves. all objects emit and absorb radiation, the amount determined by its surface area and temperature. hotter objects emit more radiation and cooler objects absorb more.

Question 25

Describe weather systems in terms of convection phenomena.

Answer 25

convection currents in atmosphere form clouds, wind patterns and distribute heat around the globe.

Question 26

Describe ocean currents in terms of convection phenomena.

Answer 26

convection currents in ocean redistribute heat and nutrients. influencing climate and marine systems.

Question 27

Describe heating and cooling systems in terms of convection phenomena.

Answer 27

convection currents are utilized in devices like radiators, ac and fans to distribute heat/cool air evenly around the area efficiently.

Question 28

How is radiation emission related and temperature?

Answer 28

the rate of radiation is directly proportional to the fourth power of its temperature. so if it increases temp then the emissions of thermal radiation increases too.

Question 29

How is radiation absorption related to the surface of objects?

Answer 29

objects absorb radiation from surroundings based on their surface. dark and rough surfaces absorb more than light and smooth (they reflect the radiation).

Question 30

How can you reduce unwanted energy transfer?

Answer 30

insulation, creating a barrier to stop the flow of heat energy between two regions.

Question 31

Do insulation materials have high or low thermal conductivity?

Answer 31

low thermal conductivity to reduce heat transfer.

Question 32

What are some ways of reducing unwanted energy transfer/insulation?

Answer 32

thermal insulation, double glazing, draft exclusion, reflective surfaces

Question 33

What is the earths gravitational field strength?

Answer 33

9.8N or 10N

Question 34

What is the principle of conservation of energy in terms of KE and GPE?

Answer 34

when an object falls the total amount of GPE lost is the total amount of KE gained. because GPE is converted to KE.

Question 35

What is the link between GPE and work done?

Answer 35

work done by gravity is the same as the GPE.

Question 36

What are the energy transfers involving generating electricity?

Answer 36

wind turbines, water, geothermal resources, solar heating systems, solar cells, fossil fuels and nuclear power

Question 37

What are the energy transfers of wind turbines?

Answer 37

kinetic energy of moving air turns into mechanical energy in the turbine which transfers to electrical energy

Question 38

What are the energy transfers of water?

Answer 38

kinetic energy of flowing water turns into mechanical energy in the water turbine which transfers to electrical energy

Question 39

What are the energy transfers of geothermal resources?

Answer 39

heat energy from the earths interior turns into steam which turns into mechanical energy in the turbine which transfers to electrical energy

Question 40

What are the energy transfers of solar heating systems?

Answer 40

solar energy turns into heat energy

Question 41

What are the energy transfers of solar cells?

Answer 41

solar energy from the sunlight turns into electrical energy

Question 42

What are the energy transfers of fossil fuels?

Answer 42

chemical energy turns into heat energy which turns into mechanical energy which then transfers to electrical energy

Question 43

What are the energy transfers of nuclear power?

Answer 43

nuclear reactions create heat energy which turns into mechanical energy which then transfers into heat energy

Question 44

What are the advantages of renewable energy resources?

Answer 44

it reduces emissions and has a low operating cost

Question 45

What are the disadvantages of renewable energy resources?

Answer 45

high upfront costs and low availability

Question 46

What are the advantages of non-renewable energy resources?

Answer 46

reliable with established infrastructures and cheap.

Question 47

What are the disadvantages of non-renewable energy resources?

Answer 47

they release emissions, nuclear waste and impact the environment negatively

Question 48

What are renewable energy sources?

Answer 48

Wind
Water (hydroelectric power)
Geothermal resources
Solar heating systems
Solar cells

Question 49

What are the non-renewable energy sources?

Answer 49

Fossil fuels (coal, oil, natural gas)
Nuclear power