P1 - Energy

Question 1

Define renewable energy

Answer 1

An energy source that is replaced faster than it can be used

Question 2

Give examples of renewable energy sources.

Answer 2

Wind, waves, tides, hydroelectric, biofuel, geothermal, solar

Question 3

How does the step-up transformer increase the efficiency of the National Grid?

Answer 3

It increases the voltage and decreases the current, therefore reducing energy loss along the cables.

Question 4

Explain one effect burning fossil fuels has on the environment.

Answer 4

produces greenhouse gases, nitrogen oxides (trigger asthma attacks), sulphur dioxide (leads to acid rain)

Question 5

Pumped storage hydroelectric power stations have a short start-up time. Why is this important?

Answer 5

to meet surges in demand/ start generating electricity in a short time

Question 6

Give an advantage of a pumped storage hydroelectric power station.

Answer 6

can store energy for later use renewable

Question 7

Using mainly wind turbines to supply electricity might cause fluctuations in the electricity supply. Why?

Answer 7

wind speeds fluctuate so turbines don’t generate electricity at a constant rate

Question 8

Between 2002 and 2008 the amount of electricity used in the UK decreased. Suggest why.

Answer 8

energy efficient lighting used/ developed; increase in energy costs so people switch off more; ‘switch off’ campaign raises awareness of environment

Question 9

Although gas boilers are very efficient, some energy is wasted. What happens to this waste energy?

Answer 9

it is transferred to the surroundings, becomes spread out; wasted as sound

Question 10

Give a disadvantage of a large scale hydroelectric power station.

Answer 10

large areas of land flooded, homes and habitats destroyed

Question 11

What is the National Grid?

Answer 11

system of cables and transformers

Question 12

Why is transferring electricity directly to local homes more efficient than using the National Grid?

Answer 12

less energy is wasted as the cables used are shorter

Question 13

A solar cell can be used to recharge a mobile phone. Suggest and explain one factor that would affect the charging time.

Answer 13

time of day, position of solar cell, angle of solar cell towards Sun, latitude, cloud cover, dust; all cause a change in light intensity

Question 14

What are the advantages of using solar cells instead of fossil fuel power stations to generate electricity?

Answer 14

no air pollution, free resource, renewable, usable in remote areas, no need to connect to National Grid

Question 15

Fitting a new hot water boiler costs £1800 but saves £200 per year. What is the payback time?

Answer 15

9 years

Question 16

Explain why using an energy efficient light bulb rather than an ordinary light bulb reduces carbon dioxide emissions.

Answer 16

less electricity needs to be generated from power stations, less fossil fuel needs to be burnt

Question 17

Give two advantages of burning wood instead of coal.

Answer 17

carbon neutral, renewable, conserves fossil fuel reserves

Question 18

Why do wood burning stoves have a large surface area?

Answer 18

to increase the rate of energy transfer

Question 19

Do you agree with the statement that ‘replacing old freezers with more energy efficient freezers’ benefits the environment?

Answer 19

y- less fossil fuels burnt as less electricity needed, so fewer greenhouse gases emittedn- old freezers must be dumped and there are hazardous chemicals inside them

Question 20

How do you reduce energy loss from the loft/roof?

Answer 20

Fibreglass

Question 21

How do you reduce energy loss from the walls?

Answer 21

Cavity wall insulation such as polystyrene beads

Question 22

How do you reduce energy loss from windows?

Answer 22

double/ triple glazing

Question 23

How do you reduce energy loss from doors?

Answer 23

draught excluders

Question 24

why are electricity companies selling electricity at night at a lower rate?

Answer 24

Supply exceeds demand

Question 25

Leaving a 1kW radiator switched on for the same length of time as a 40W lamp is worse for the environment. Why?

Answer 25

radiator uses more energy,more electricity is needed,more fossil fuel is burnt, moreCO2 produced

Question 26

What is meant by the word efficient?

Answer 26

most input energy isusefully transformed

Question 27

Give examples ofstored energy.

Answer 27

gravitational, elastic,chemical

Question 28

Why must the totalenergy input equal the totalenergy output?

Answer 28

energy cannot be createdor destroyed

Question 29

Name the useful andwasted energy output from ahair dryer.

Answer 29

useful thermal and kineticand wasted sound energy

Question 30

Name the useful andwasted energy output from aTV.

Answer 30

useful sound and light,wasted thermal

Question 31

what does it mean todecommission a nuclearpower station?

Answer 31

remove radioactive waste/fuel- very expensive process

Question 32

How could companiesreduce CO2 emissions?

Answer 32

use more nuclear power,use more renewable energysources, use carbon capturetechnology

Question 33

Give the advantages ofusing nuclear power.

Answer 33

little fuel needed for a largeamount of energy released(concentrated source of energy),continuous process, nogreenhouse gas emissions

Question 34

give advantages anddisadvantages of tidal powergenerating systems.

Answer 34

renewable, calms coastalwaters, low running costs, noair pollution but highinstallation costs, timedependent, disturbs coastalhabitats

Question 35

Give advantages anddisadvantages of wind power.

Answer 35

renewable, no air pollution,leave land undamaged whenremoved but unsightly andnoisy, require large areas ofland as many turbines areneeded

Question 36

How does a vacuumflask keep the liquid insidehot?

Answer 36

plastic cap is poor conductor & stopsevaporation of hot liquid as particlescannot escape; stops convectioncurrents so no heat loss by convection;vacuum prevents heat loss byconduction & convection as both requireparticles; silver lining to reflect IR backinside the flask and reduce heat loss byradiation

Question 37

Why do arctic foxes havesmall ears?

Answer 37

ears have a small surfacearea so reduce heat loss

Question 38

Why is foam a goodinsulator?

Answer 38

air cannot circulate insidefoam as the air bubbles aretrapped inside the foam

Question 39

What is meant by theterm U-value?

Answer 39

how effective an insulator amaterial is; the lower the Uvalue,the better the material isat insulating

Question 40

What is geothermalenergy?

Answer 40

energy from hot rocks inthe Earth

Question 41

Why does theNational Grid include step-uptransformers?

Answer 41

to increase the voltageacross the cables and reduceenergy loss

Question 42

Why are copper pipesinside a solar panel paintedblack?

Answer 42

black is a goodabsorber of radiation sothere will be a fastertransfer of energy to thewater

Question 43

Why is electricityessential for moderncommunication and publichealth?

Answer 43

Many devices transform onetype of energy into others;doctors and hospitals can storevaccines and blood inrefrigerators; internet runs onelectricity

Question 44

What is the role ofthe step-down transformer?

Answer 44

It reduces the voltage to asafe working value for homesand offices