y9 revision 2

Question 1

list the 8 energy stores

Answer 1

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

Question 2

name the four ways in which energy can be transferred

Answer 2

electrical, radiation, mechanical, heating

Question 3

what is a closed system

Answer 3

where neither matter nor energy can enter or leave. the net charge in the total energy of closed system is always zero

Question 4

what is the unit of energy?

Answer 4

joules (j)

Question 5

what is gravitational potential energy equation, with units?

Answer 5

Ep= mgh
GPE = joules (j)
mass = kilograms (kg
height - metres (m)

Question 6

what is the kinetic energy equation, with units?

Answer 6

Ek = 0.5 mv^2 
KE = joules (j) 
mass = kilograms (kg) 
speed = metres per second (m/s)

Question 7

what is the law of conservation of energy?

Answer 7

energy is not created or destroyed but transferred from one store to another

Question 8

what is the equation of power? with units

Answer 8

P = E/t 
Power = watts (w) 
Energy = joules (j) 
Time = seconds (s)

Question 9

where is heat lost in a house?

Answer 9

windows, roof, walls, doors and floors

Question 10

what is the efficiency equation?

Answer 10

Efficiency = useful energy/ total energy 
Efficiency = useful power/ total power

Question 11

define the term power

Answer 11

the rate of transfer of energy

Question 12

describe the energy transfer when a moving car slows down

Answer 12

energy is transferred mechanically from the kinetic store of the car to the thermal store of the surrounding
some energy is dissipated to the thermal store of the surrounding

Question 13

describe the energy transfer when electric kettle is used an elastic band

Answer 13

the electric current in a kettle transfers energy to the heating element’s thermal store of the surroundings

Question 14

describe the energy transfer when battery powered toy car is used

Answer 14

energy is transferred electrically from chemical store of the battery to the kinetic store of the toy car - some of the energy is dissipated to the thermal store of the surrounding

Question 15

describe the energy transfer when a falling apple hits the ground

Answer 15

energy is transferred from kinetic store of the apple and dissipated to the thermal store of surroundings by sound waves

Question 16

name the unit that represents one joule transferred per second

Answer 16

watts (w)

Question 17

what is work done?

Answer 17

energy transferred when force moves an object

Question 18

what would happen to the kinetic energy of the mass of the object double, but the speed stayed the same?

Answer 18

the kinetic energy would double

Question 19

what would happen to the kinetic energy of the speed of the object double, but the mass of the object stayed the same?

Answer 19

the kinetic energy would be quadruple

Question 20

what is the elastic potential energy equation, with units?

Answer 20

Ee= 0.5 ke^2
Elastic potential energy = joules (j)
spring constant = newton per meter (N/m)
extension = meter (m)

Question 21

what is meant by the term extension and spring constant?

Answer 21

extension is the charge in the length of the spring constant in the stiffness of the spring

Question 22

what is the meaning of specific heat capacity?

Answer 22

the specific heat capacity of a substance is the amount of energy required to raise the temperature of one kilogram of the substance by one degree Celsius

Question 23

what is the equation for specific heat capacity? with units

Answer 23

△E = mc △0 (line in the 0) 
change in thermal energy, △E, in joules, J 
mass = kilograms, kg 
specific heat capacity, J/kg °C
temperate change = °C

Question 24

what is the dependent, independent and control variable for the specific heat capacity practical?

Answer 24

Independent variable is the energy transfer
dependent variable is the temperature change
control variable are insulation (quantity and type), same heater, same method of transferring energy

Question 25

describe the ways to reduce heat loss in a house

Answer 25

windows ~ double glazing, air gap between the two sheets of glass to prevent energy transfer by conduction thick curtains ~ the cloth over the window creates air gap between the room and the window which reduces the energy transfer by conduction roof ~ loft insulation, thick layer of fibreglass reduces conduction as it traps pockets of air walls ~ cavity wall insulation, the air gap reduces the amount of energy transferred by conduction through the wall doors ~ draught excluders, stops draught blowing in and out and reduces energy transfer by convection

Question 26

name the renewable and non - renewable resources of energy?

Answer 26

non - renewable ~ coal, oil , gas and nuclear | renewable ~ solar energy, wind turbine, waves, geothermal, tidal, hydroelectric, biomass

Question 27

list the advantages of fossil fuels

Answer 27

readily available enough resource to meet the current demand. reliable source of energy cheap to extract and use

Question 28

list the disadvantages fossil fuels

Answer 28

releases carbon dioxide into the atmosphere which contributes to global warming releases sulphur dioxide into the atmosphere which causes acid rain going to run out

Question 29

list the advantages of nuclear power

Answer 29

lots of energy releases from a small amount of fuel reliable can control supply to match the demand enough fuel available to meet the current demand no polluting gases

Question 30

list the disadvantages of nuclear power

Answer 30

waste is dangerous and difficult and expensive to deal with expensive initial set up expensive to shut down and to run

Question 31

list the advantages of solar energy

Answer 31

can be used in remote places no polluting gases no waste products very low running costs

Question 32

list the disadvantages of solar energy

Answer 32

unreliable cannot control supply initial set up expensive cannot be used on a large scale

Question 33

list the advantages of wind power

Answer 33

clean renewable source of energy relatively low set up cost pre unit of electricity generated large potential both on and offshore in the UK wind farms tend to produce more electricity in the winter when demand is also higher

Question 34

list the disadvantages of wind power

Answer 34

wind power is not reliable, if wind is light then no power generated some people do not like the look of them potentially harm some birds some people do not want them near their home due to visual impact and noise

Question 35

list the advantages of tidal power

Answer 35

``` now polluting gases no waste products reliable can produce large amounts of electricity low running cost no fuel costs ```

Question 36

list the disadvantages of tidal power

Answer 36

``` can harm marine habitat initial set up expensive cannot increase supply when needed amount of energy varies on time of month hazard for boats ```

Question 37

list the the advantages of wave turbines

Answer 37

no polluting gases produced no waste products low running cost no fuel cost

Question 38

list the advantages of wave turbines

Answer 38

``` unreliable, dependent on weather cannot control supply initial set up expensive can harm marine habitats hazard for boats cannot be used on a large scale ```

Question 39

list the advantages of geothermal energy

Answer 39

clean and renewable no air pollution or carbon dioxide production minimal damage to the environment constant source of energy

Question 40

list the disadvantages of geothermal energy

Answer 40

only a few places on Earth are suitable where the Earth’s core is close enough to the surface to make use of the geothermal energy Expensive and difficult to drill deep into the ground

Question 41

list the advantages of biofuels

Answer 41

carbon neutral fuel as carbon dioxide is absorbed when growing so it does not add to the overall carbon dioxide in the atmosphere can be used to replace the burning of fossil fuels like coal in power stations

Question 42

list the disadvantages of biofuels

Answer 42

emits carbon dioxide and soot when burnt bulky to transport requiring large volumes for the same energy output compared to fossil fuels requires energy to transport and process