4 Energy resources and energy transfers

Question 1

Energy Stores

Answer 1

• Chemical
• Kinetic
• Gravitational
• Elastic
• Thermal
• Magnetic
• Electrostatic
• Nuclear

Question 2

Energy Transfers

Answer 2

• Mechanically
• Electrically
• By heating
• By radiation (light, sound)

Question 3

Principle of the conservation of energy

Answer 3

Energy cannot be created or destroyed, but can be transferred from one store to another

Question 4

Equation for efficiency

Answer 4

useful energy output/total energy input
x 100

Question 5

How can thermal energy transfer occur?

Answer 5

• Conduction
• Convection
• Radiation

Question 6

Conduction

Answer 6

Transfer of thermal energy (heat) through the vibrations of atoms in a solid

Question 7

Convection

Answer 7

Transfer of thermal energy (heat) through fluids (liquids or gases) by the upwards movement of warmer less dense regions of fluid

Question 8

Convectional Current

Answer 8

• Air is heated
• So it expands
• So becomes less dense
• So the air rises

Question 9

Radiation

Answer 9

• Transfer of thermal energy (heat) through infrared waves (IR)
• IR waves can travel in a vacuum (at the speed of light)

Question 10

Why can conduction only occur in solids?

Answer 10

The particles are packed tightly together, so energy can be transferred from one particle to another

Question 11

How do IR waves travel?

Answer 11

• Travels in straight lines
• Falls upon objects

Question 12

What are conductors in relation to insulators?

Answer 12

Best conductors = Worst insulators
Worst conductors = Best insulators

Question 13

Order of States of Matter from Best -> Worst Conductor / Worst insulator -> Best Insulator

Answer 13

• Metallic Solids
• Liquids
• Gases

Question 14

Why are gases bad conductors?

Answer 14

There is no bonding between the particles so heat cannot be transferred from one particle to the other

Question 15

What are absorbers in relation to emitters?

Answer 15

• Good absorbers = good emittors
• Bad absorbers = bad emittors

Question 16

Order of States of Matter from Good absorbers + emittors -> bad absorbers + emittors

Answer 16

• Dull black
• White
• Shiny silver (good reflector)

Question 17

Are good reflectors bad absorbers + emittors?

Answer 17

Yes

Question 18

How does heat travel?

Answer 18

Hot -> Cold

Question 19

Investigating Conduction

Answer 19

Conduction ring with bars of differnet metals with drawing pin attached with petroleum jelly
Heated

The metal of the drawing pin that falls off first is the best conductor

Control variable: Size of pins, distance of bars from heat source

Question 20

Investigating Convection currents in water

Answer 20

• Put a crystal of potassium permanganate in the middle of a beaker of water
• Heat gently
• Observe spread of purple

Question 21

Investigating Convection currents in gases

Answer 21

• Box with 2 chimneys, with lit candle under 1 chimney
• Air warms up, floats up the chimney, and cold air is drawn into the other chimeny.

Question 22

Investigating how well different objects radiate heat

Answer 22

• Light bulb, half painted black, and half painted shiny white
• Thermometers on either side
• Greater temp. rise on black side, so black is a better radiator of heat

Question 23

Ways of reducing unwanted energy transfer

Answer 23

• Clothes
• Silver foil blanket
• Energy efficient homes

Question 24

Reducing unwanted heat transfer: Clothes

Answer 24

• Trap air, which is a bad conductor of heat/good insulator

Question 25

Reducing unwanted heat transfer: Silver foil blanket

Answer 25

* Inside surface reflects heat back to person * Outside surface is a bad emittor

Question 26

Reducing unwanted heat transfer: Silver foil blanket

Answer 26

* Inside surface reflects heat back to person * Outside surface is a bad emittor

Question 27

Reducing unwanted heat transfer: Energy efficient homes

Answer 27

* Insulation - traps air to reduce heat loss, stops formation of convection current * Double glazing windows - increases greenhouse effect * Eliminating draughts by fixing windows + doors properly

Question 28

Work Done

Answer 28

Energy transferred (from one store to the other)

Question 29

Equation for work done

Answer 29

Work Done = Force x Distance Moved W = Fd

Question 30

Equation for Gravitational Potential Energy (GPE)

Answer 30

GPE = mgh

Question 31

Equation for Kinetic Energy

Answer 31

K.E. = 1/2mv(squared)

Question 32

Power

Answer 32

* Rate of energy transfer * Rate of doing work

Question 33

Equation for Power

Answer 33

* Power = Work done/time taken * Power = Energy transferred/time taken

Question 34

What process do radiators do?

Answer 34

Convection

Question 35

How are radiators designed to help maximise heat transfer by convection?

Answer 35

Have curves to increase surface area

Question 36

How is electricity generated?

Answer 36

1. Energy stored in fossil fuels is **used to heat water** 2. Heat energy in high pressure steam **drives a turbine** 3. Kinetic energy of turbine **spins generator ** 4. Electrical energy output

Question 37

Energy transfers involved in the generation of electricity

Answer 37

Chemical -> Thermal -> Kinetic -> Electrical

Question 38

Renewable

Answer 38

The energy resource will not run out

Question 39

Non - renewable

Answer 39

The energy resource will run out

Question 40

Ways of generating electricity

Answer 40

* wind * water * geothermal resources * solar heating systems * solar cells * fossil fuels * nuclear power

Question 41

Fossil Fuels

Answer 41

* Non - renewable * Coal, oil, gas

Question 42

Advantages of Fossil Fuels

Answer 42

* Releases lots of energy, relatively cheaply * Reliable (not reliant on weather

Question 43

Disadvantages of Fossil Fuels

Answer 43

* Releases CO2 when burned -> contributes to global warming/climate change * Burning coal + oil releases sulfur dioxide -> causes acid rain

Question 44

Nuclear Fuel

Answer 44

Uses nuclear fission of uranium to release heat energy

Question 45

Advantages of Nuclear Fuel

Answer 45

* Clean -> no greenhouse gases produced * Reliable

Question 46

Disadvantages of Nuclear Fuel

Answer 46

* Expensive to build + maintain * Risks of radioactive material leaks

Question 47

Geothermal Energy

Answer 47

* Renewable * Uses thermal energy underground (from radioactive decay) * Cold water is pumped into the ground, and the steam produced is pumped up

Question 48

Advantages of Geothermal Energy

Answer 48

* Renewable * Free * Clean

Question 49

Disadvantages of Geothermal Energy

Answer 49

* Expensive to drill deep down * Can only be built in a few places

Question 50

Wind Power

Answer 50

* Wind Turbines * Winds are powered by Sun's heat energy

Question 51

Advantages of Wind

Answer 51

* Clean * Renewable

Question 52

Disadvantages of Wind

Answer 52

* Ruins landscape * Noise pollution * May kill birds * Expensive to setup/maintain * Unreliable

Question 53

Wave Energy

Answer 53

* Uses kinetic energy of waves

Question 54

Advantages of Wave Energy

Answer 54

* Renewable * No pollution

Question 55

Disadvantages of Wave Energy

Answer 55

* Unreliable

Question 56

Tidal Power

Answer 56

* Tidal barrages = big dams where the river joins the sea * The movement of tides is caused by the gravitational pull of the Sun and Moon

Question 57

Advantages of Tidal Power

Answer 57

* No pollution * Renewable

Question 58

Disadvantages of Tidal Power

Answer 58

* Damages wildlife habitat * Ruins landscape

Question 59

Hydroelectric Power

Answer 59

* Dam built in mountains/valleys * Rainwater is collected, then released at once

Question 60

Advantages of Hydroelectric Power

Answer 60

* Renewable * Clean

Question 61

Disadvantages of Hydroelectric Power

Answer 61

* Floods the mountains/valleys * Loss of habitat for wildlife

Question 62

Types of Solar Heating Systems

Answer 62

* Solar water heating panel * Solar power

Question 63

Solar Water Heating Panels

Answer 63

Glass lets heat energy from Sun in, and is absorbed by black pipes -> heats water

Question 64

Advantages of Solar Water Heating Panels

Answer 64

* Renewable * Free

Question 65

Disadvantages of Solar Water Heating Panels

Answer 65

Expensive to setup

Question 66

Solar Power

Answer 66

Photovoltaic cells transfer light energy -> electric energy

Question 67

Advantage of Solar Power

Answer 67

* Renewable Clean

Question 68

Disadvantage of Solar Power

Answer 68

* Loss of farmland