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Question 1

Explain what conduction is

Answer 1

Conduction is the main form of heat transfer in solids, conduction of heat energy is the process where vibrating particles pass on their extra kinetic energy to neighbouring particles.

Question 2

Explain what radiation is

Answer 2

Heat radiation is the transfer of heat energy by infrared (IR) radiation. All objects are continually emitting and absorbing infrared radiation, it is emitted from the surface of an object. An object thats hotter than its surroundings emits more radiation than it absorbs (as it cools down). An object thats cooler than its surroundings absorbs more radiation than it emits (as it warms up).

Question 3

Describe how and why different surfaces affect radiation

Answer 3

Dark, matt surfaces absorb infrared radiation much better than light, shiny surfaces, such as gloss white or silver. They also emit much more infrared radiation (at any given temprature) light shiny surfaces reflect radiation which is why they are used in the inside of flasks to keep hot/cool air in/out of it

Question 4

Describe the structure of a solid

Answer 4

Solids have strong forces of attraction to hold the particles close together in a fixed, regular arrangement. The particles only have enough energy to vibrate in their fixed positions

Question 5

Describe the structure of a liquid

Answer 5

Liquids have weaker forces of attraction between the particles. The particles are close together, but can move past each other, and form irregular arrangements. They have more energy than the particles of a solid so can move in random directions at low speed

Question 6

Describe the structure of gases

Answer 6

There are almost no forces of attraction between the particles. The particles have more energy than those in liquids and solids, they are free to move and travel in random directions in high speed

Question 7

Why are metals such good conductors?

Answer 7

Metals conduct so well because the electrons are free to move inside the metal. At the hot end, the electrons move faster and collide with other free electrons, transferring energy. These other electrons then pass on their energy to other electrons etc.Because the other electrons can move freely this is obviously a much faster way of transferring energy.

Question 8

What is the radiator example of convection?

Answer 8

Heating a room with a radiator relies on convection currents too. Hot, less dense released by the radiator rises and denser, cooler air flows to replace it, it then gets hot and then rises and replaces the what was hot air which has cooled down

Question 9

What is condensation?

Answer 9

When a gas cools the particles slow down and lose kinetic energy. The attractive forces between the particles pull them closer together. If the temperature gets cold enough and the gas particles get close enough together that condensation can take place, the gas becomes a liquid. Water vapour in the air condenses when it comes in contact with a cold surface, eg drinks glases

Question 10

Explain what convection is

Answer 10

Convection is the main form of heat transfer in liquids and gases it occurs when the more energetic particles move from the hotter region to the cooler region and take their heat energy with them.

Question 11

Explain what evaporation is

Answer 11

Evaporation is when particles escape from a liquid. They can evaporate from a liquid at temperatures that are much higher than the liquids boiling point, the fastest particles with the most kinetic energy are most likely to evaporate from the liquid so when they do, the average speed and kinetic energy of the remaining particles decreases. This decrease in average particle energy means the temprature of the remaining liquid falls, this is called the cooling effect, it can be very useful when your sweating your sweat evaporates and cools you down.

Question 12

What ways do humans have of controlling heat transfer?

Answer 12

In the cold hairs on your skin stand up to trap a thick layer of insulating air around the body. This limits the amount of heat loss by convection. Some animals do the same with fur. When your too warm, your body diverts more blood to flow near the surface of your skin so that more heat can be lost by radiation, this limits the amount of heat loss by convection.

Question 13

What ways do animals have of controlling body temperature?

Answer 13

Generally in warmer climates, animals have larger ears than those in colder climates to help control heat transfer. For example, arctic foxes have evolves small ears, with a small surface area to minimise heat loss by radiation and conserve body heat. Desert foxes on the other hand have huge ears with a large surface area to allow them to lose heat by radiation and easily keep cool.

Question 14

what is payback time

Answer 14

initial cost over annual savings

Question 15

what is cavity wall insulation

Answer 15

foam squirted into the gap between the bricks stops convection currents being set up in the gap and radiation across the gap

Question 16

what is loft insulation

Answer 16

a thick layer of fibreglass wool laid our across the whole loft floor, reduces conduction and radiation

Question 17

what is fraught proofing

Answer 17

strips of foam and plastic around doors and windows stop draughts they reduce heat loss due to convection

Question 18

what is hot Walter tank jacket

Answer 18

fibreglass wool, reduces conduction and radiation

Question 19

what are thick curtains

Answer 19

big bits of cloth over the window to reduce heat loss by conduction and radiation

Question 20

what is. a specific heat capacitors

Answer 20

it takes heat energy to increase the temperature of some materials than others. it tells you how much energy things can store. material which need to gain a lot of energy to warm up also release loads of energy when they cool down. they can store a lot of heat. it is the amount of energy needed to ease the temperature of 1 kg of a substance by 1oC

Question 21

what is the formula for specific heat capacity

Answer 21

e energy transferred = m mass X c specific heat capacity X Greek o temperature change

Question 22

triangle of specific heat capacity

Answer 22

e

mco

Question 23

name some properties heaters have

Answer 23

the materials used in heaters usuailly have high specific heat. capacities so. to store a high amount of heat energy.

water has a very high SHC it is also a liquid so can be pumped easily around which is why it is ideal for central heating systems in buildings

some heaters are filled with oil which has a specific heat capacity of around 2000 j/kg oC this is. lower than waters but has a higher boiling point than water so can be safely heated to a higher point

Question 24

tell me about the cheeky 9 types of energy

Answer 24

electrical energy, whenever a current flows
light energy, from the sun light bulbs etc
sound energy, from loudspeakers or anything noisy
kinetic energy, anything that’s moving has it
nuclear energy, released from only nuclear reactions
thermal energy, flows from hotter objects to cooler ones
gravitational potential energy, powered by anything which can fall
elastic potential, stretched springs rubber bands elastic etc
chemical energy, processed by foods fuels batteries etc

Question 25

what is the conversion of energy principle

Answer 25

energy can be transferred usefully from one form to another. stored of dissipated but it can never be created or destroyed

Question 26

what makes energy useful

Answer 26

if it's able to be converted from one form to another

Question 27

how do you calculate energy efficiency

Answer 27

useful NRG in over total NRG out nandos

Question 28

how would you show efficiency

Answer 28

as a decimal or a percentage

Question 29

is there a device that is 100% efficient

Answer 29

yes the electric heater because. it has no. wasted energy

Question 30

what is wasted. energy

Answer 30

energy that is produced. in a device but not wanted eg heat on a computer

Question 31

What are kWh?

Answer 31

kWh are units of energy, electrical appliances transfer electrical energy into other forms, eg sound or heat energy in a radio. The amount of energy that is transferred by an appliance depends on its power (how fast the appliance can transfer it) and the amount of time the appliance has been switched on.

Question 32

explain kWh

Answer 32

Energy is usually measured in joules (j) 1 j is the amount of energy transferred by a 1 W appliance in 1 second. Power is measured in watts (w) or kilowatts (kW) a 5 kW appliance transfers 5000 J in one second. The standard units of electrical energy are kilowatt hours not joules.

Question 33

How do you figure out the cost and amount of energy used?

Answer 33

Number of units (kWh) used = power (in kWh) X time (h) | Cost = number of units X price per unit

Question 34

How do you find the total energy from meter readings?

Answer 34

Take the larger number of the meters and subtract the smaller one from it

Question 35

How is the standard of living affected by electricity

Answer 35

Light energy is not only useful in the day but safe at night, refrigerators keep food fresh by slowing the growth of bacteria and also used to keep vaccines cold, this would have a devastating affect on the country if they weren't kept cold. Hospitals use X Ray's to find injuries also electricity is vital to communication.

Question 36

List some non renewable energy sources

Answer 36

Coal Oil Natural gas Nuclear fuels (uranium and plutonium)

Question 37

List some renewable energy sources

Answer 37

``` Wind Waves Tides Solar Hydroelectric Geothermal Food Biofuels ```

Question 38

How are fossil fuels used to provide electricity?

Answer 38

The is burnet to convert its stored chemical energy into heat (thermal energy). The heat energy is used to heat water (or air in some fossil fuels power stations)to produce steam. The steam turns a turbine, converting heat energy into kinetic energy, the turbine is connected to a generator, converting kinetic energy into electrical energy. A nuclear power station is the same as this but with uranium or plutonium

Question 39

How are non renewable energy sources linked to environmental problems?

Answer 39

When these fuels are burned, they release CO2 into the atmosphere, this co2 adds to the greenhouse effect, this contributes to global warming, burning coal releases sulphur dioxide, this leads to acid rain which can cause harm to plants and trees. Coal mining can lead to damage in landscapes especially open cast mining. Oil spillages cause serious environmental problems, affecting mammals and birds that live in and around the sea, we try to avoid them, but they'll always happen. Nuclear power is clean but nuclear waste is dangerous and very difficult to dispose of. Nuclear power always carries the risk of a major catastrophy like the Chernobyl disaster in 1986

Question 40

Describe different types of energy set up costs

Answer 40

Renewable resources often need bigger power stations that non-renewables for the same output. The bigger the power station the more expensive. Nuclear reactors and hydroelectric dams also need huge amounts of engineering to make them safe, which bumps up the cost

Question 41

Describe the different power sources set up / decommissioning time

Answer 41

these are both affected by the size of the power station, the complexity of the engineering and also the planning issue (eg. the discussions over whether a nuclear power station should be built over a stretch of beautiful coastline can take years). Gas is one of the quickest to set up. Nuclear power stations take by far the longest (and cost the most) to decommission

Question 42

Describe the different sources of energy running/fuel costs

Answer 42

Renewables usually have the lowest running cost because there's no actual fuel involved

Question 43

Describe the different sources of energys reliability issues

Answer 43

All non renewables are reliable energy providers until they run out many of the renewable sources depend on the weather, which means they're pretty unreliable here in the UK. The exceptions are tidal power and geothermal which don't depend on weather

Question 44

Describe the different types of energys environmental issues

Answer 44

Is there is a fuel involved there will be waste pollution and you'll be using up resources. If it relies on the weather, it's often got to be in an exposed place. - Atmospheric pollution - Using up resources - Visual pollution - Noise pollution - Disruption of leisure activities

Question 45

describe the location issues of the sources of energy

Answer 45

Solar, anywhere with sun Gas, anywhere Hydroelectric, hilly, rainy floodable valleys Wind, exposed windy places Oil, near the coast because oil is transported by sea Waves, in the sea... Coal, near coal mines Nuclear, Away from people near water for cooling Tidal, in a big river where a dam can be built Geothermal, where hot rocks are near the earths surface

Question 46

What is the national grid?

Answer 46

The national grid distributes energy from power stations to where it's needed in homes and industry Power can be generated anywhere on the grid and supplied anywhere else on the grid. To transmit the power needed a high voltage or current is needed A high current loses a lot of energy through heat in cables It's cheaper to boost the voltage higher and keep the current low

Question 47

What are pylons and transformers?

Answer 47

The get the voltage up to 400000V to transmit power requires transformers as well as big pylons with huge insulators but it's still cheaper Transformers haft to step up the voltage at one end, for efficient transmission, and then bring it back down to safe, usable levels at the other end. The voltage is stepped up using a step up transformer and stepped down with a tree down transformer

Question 48

Explain the supply and demand of the national grid

Answer 48

It needs to generate and direct all energy we need and it keeps on increasing. To make demands the energy supplied needs to increase or demands need to decrease. Supply can increase by opening more power plants by opening more power plants or increasing their power output (or both). Demands can be reduced by consumers using more energy efficient appliances and being more careful not to waste energy in the home (e.g. turning off the lights)

Question 49

What are the parts of a wave

Answer 49

Amplitude is from the center to the top or bottom of the wave. The wavelength is the stretch between the 2 tops of the wave. the crest is the top of the wave, rest position is the centre line

Question 50

What is a transverse wave?

Answer 50

A wave that has sideways vibrations eg ripples on water or light

Question 51

what is a longitudinal wave?

Answer 51

A wave that has vibrations along the same line eg a slinky pushed at one end or sound waves

Question 52

How do you find wave speed?

Answer 52

Frequency X Wavelength

Question 53

Name 3 properties of a wave

Answer 53

all waves can be reflected, refracted and diffracted

Question 54

what is the angle of incidence the same as?

Answer 54

The angle of reflection

Question 55

Explain diffraction of waves

Answer 55

All waves spread out at the edges when they pass through a gap or pass an obstacle. the narrower the gap or longer the wavelength, the more the wave spreads out. A narrow gap that is the same order of magnitude as the wavelength. eg light needs a very narrow gap because the wavelength is only 0.0005 mm

Question 56

explain wave refraction

Answer 56

When a wave crosses a boundary between two substances it changes direction. They are only refracted if the meet the medium at an angle, if they meet at a straight angle they will change speed but they are not refracted so don't change direction

Question 57

in order from longest wavelength to shortest name the electromagnetic waves

Answer 57

``` Radio waves Micro waves Infra red Visible light Ultra violet X-Ray's Gamma rays ``` Rock music is very useful for xperiments with goats

Question 58

What are radio waves used for and why

Answer 58

Radio waves are used for communication, this is because they have wavelengths of over 10cm, because they have long wavelengths, they are able to go around the world because they diffract around the curved surfaces of the world.

Question 59

What are microwaves used for and why?

Answer 59

Microwaves are used for satellite communication and mobile phones, this is because microwaves can easily pass through earths watery atmosphere and radio waves can't do this. For satellite to, the signal from a transmitter is transmitted into space, it is picked up by the satellites receiver dish and the satellite transmits the radiowaves back to earth in a different direction and received by a satellite dish on the ground

Question 60

What are infrared waves used for?

Answer 60

They are used in wireless remote controllers. Remote controllers work by emoting different patterns of infrared waves to send different commands to an appliance eg TV. They are also used in optical fibres. These can carry data over long distances very quickly.

Question 61

What are visible light waves used for

Answer 61

These are used for photography, cameras use a lens to focus visible light onto a light-sensitive film or electronic sensor. The aperture controls how much light enters the lens. The shutter speed controls how long the film or sensor is exposed to the light. These can all be varied to control the picture

Question 62

What are sound waves

Answer 62

Sound waves are caused by vibrating objects. These mechanical vibrations are passed through the surrounding medium as a series of compressions. They're a type of longitudinal wave. It travels into the ear and eardrum and this causes hearing. It travels faster in solids than liquids and liquids than gases. sound can't travel in space as it is mostly a vacuum

Question 63

explain the retractions and reflections of sound waves

Answer 63

Sound waves will be reflected by hard flat surfaces. empty rooms sound different when carpet and furniture is added because it absorbs most of the sound to stop echoes. There is a delay between the original sound and the echo because the echoed sound waves take have to travel further, so can take longer to reach your ears.

Question 64

Explain the correlation between frequency and pitch.

Answer 64

The higher the frequency, the higher the pitch. frequency is the number of complete vibrations each second, a wave that has a frequency of 100hz vibrates 100 times each second, a kHz is 1000 Hz and a MHz is 1000000 Hz. High frequency or pitch also means shorter wavelength. The loudness of a sound depends on the amplitude of the sound wave, the bigger the amplitude the louder the sound.

Question 65

What is the evidence for the universe expanding?

Answer 65

different chemical elements absorb different frequencies of light, each one produces a specific pattern of dark lines at the frequency it absorbs on the visible spectrum, when we look at light from different galaxys we can see the same patterns but at slightly lower frequencies the. they should be, theyre shifted towards the red end of the spectrum. This is called red shift.

Question 66

What is the doppler effect?

Answer 66

The frequency kf a sound comming towards you will seem higher and the wavelength will seem shorter. The frequency of a sound moving away from you will seem lower and its wavelength will seem longer. It afffects both lonngitudanal waves and r transverse ones.

Question 67

What has greater red shifts, galaxies that are close or far away

Answer 67

far away

Question 68

Explain the big bang theory

Answer 68

All the matter andd energy in the universe was compressed into one tiny space and it exploded and started expanding. It is still going on, it is estimated to have started 14 billion years ago.

Question 69

What is cmbr?

Answer 69

Scientists have detected low frequency electromagnetic radiation coming from all parts of the universe. It is likely in the microwave part of the em spectrum, kts known as the cosmic microwave background radiation CMBR, the big bang theory if the only one that can explain cmbr