energy

Question 1

name the different energy stores

Answer 1

• thermal
• kinetic
• gravitational potential
• elastic
• magnetic
• chemical
• nuclear
• electrostatic

Question 2

what are the different ways energy can be transferred by

Answer 2

• mechanically
• heating
• electrically
• light
• radiation
• sound

Question 3

what is a system

Answer 3

a collection of matter

Question 4

what is kinetic energy

Answer 4

the energy an object possesses due to its motion

Question 5

what does kinetic energy depend on

Answer 5

speed and mass

Question 6

how do you calculate kinetic energy

Answer 6

kinetic energy = 1/2 x mass x speed^2

Question 7

what does the gravity experienced by two objects depend on

Answer 7

mass and how far apart those objects are

Question 8

how do you calculate weight

Answer 8

weight = mass x gravitational field strength

Question 9

what is gravitational potential energy

Answer 9

energy or work require to lift up an object against gravity

Question 10

what is the formula for gravitational potential energy

Answer 10

gravitational potential energy = mass x gravitational field strength x height

Question 11

what is internal energy

Answer 11

the total energy stored by the particles making up a substance or system
(also the amount of energy released as that substance cools down)

Question 12

what is specific heat capacity

Answer 12

the amount of energy needed to raise the temperature of 1kg of a substance by 1 degree celsius

Question 13

what is the equation for the change in internal energy

Answer 13

change in internal energy = mass x specific heat capacity x temperature change

Question 14

what is the conservation of energy principle

Answer 14

energy can be transferred usefully, stored or dissipated, but can never be created or destroyed

Question 15

what are the 3 different ways heat can be transferred and by what medium

Answer 15

conduction for solids
convection for liquids
radiation for empty space

Question 16

what is conduction

Answer 16

when vibrating particles transfer energy to neighbouring particles

Question 17

what is thermal conductivity

Answer 17

how well objects transfer energy by conduction

Question 18

what is convection

Answer 18

when heated particles with more energy move up while colder particles move down to create a convection current

Question 19

what is radiation

Answer 19

when heat to transferred through infrared waves

Question 20

how can you reduce the amount of heat energy loss

Answer 20

thermal insulation and lubrication

Question 21

what is friction

Answer 21

the resistance that an object encounters when moving over a solid, or moving through a liquid

Question 22

what is power

Answer 22

the rate at which energy is transferred or the rate at which work is done

Question 23

what is power measured in

Answer 23

watts (W)

Question 24

what is efficiency

Answer 24

proportion of energy supplied that is actually transferred into useful energy

Question 25

give examples of non-renewable energy

Answer 25

- natural gas - coal - oil - nuclear

Question 26

what is the difference between non-renewable and renewable energy sources

Answer 26

non-renewable energy sources cannot be replenished at the same rate they are being used and will therefore eventually run out. renewable energy sources can be replenished at the same or faster rate that they are being used and will therefore not run out.

Question 27

how does wind power work

Answer 27

wind is captured through turbines and turn a generator which turns kinetic energy into electric energy

Question 28

how does solar power work

Answer 28

generated by solar cells which generate electric currents directly from sunlight

Question 29

what are the pros of wind and solar energy

Answer 29

- low running cost - doesn't damage the environment - renewable

Question 30

what are the cons of wind and solar energy

Answer 30

- high upfront cost - making them does produce pollutants - dependent on the weather - no way to increase supply - take up lots of space

Question 31

what is geothermal energy

Answer 31

thermal energy generated and stored in the earth's crust

Question 32

how can geothermal energy be used for heating

Answer 32

water is pumped down into the earth's curst to heat up and then returns back to heat our homes

Question 33

how can we generate electricity using geothermal energy

Answer 33

water left until it is converted into steam, as the steam rises it turns turbines which then generate electricity

Question 34

what are the pros of geothermal energy

Answer 34

- installing only damages the environment slightly - running it doesn't produce any pollutants - reliable

Question 35

what are the cons of geothermal energy

Answer 35

- power plants can be expensive to build | - only use this source in certain areas

Question 36

what is biofuel

Answer 36

fuel thats made from recently living organisms

Question 37

where do biofuels usually come from

Answer 37

- plants - algae - animal waste

Question 38

why are carbon fuels considered carbon neutral

Answer 38

even though they release carbon dioxide, that carbon dioxide was once taken up from the atmosphere anyways

Question 39

what are the pros of biofuels

Answer 39

- cheap to make - easy to transport - can mix them with fossil fuels

Question 40

what are the cons of biofuels

Answer 40

- need somewhere to grow all these plants which will damage the environment - all the processing will require energy and release more carbon dioxide

Question 41

what is a hydroelectric dam

Answer 41

trapping water that has come from upstream to create a reservoir

Question 42

what is a tidal barrages

Answer 42

making use of tides, during high tight water is wrapped creating a difference in water level

Question 43

how do hydroelectric dams and tidal barrages create energy

Answer 43

the difference in water levels means the stored water has a huge amount of gpe which can be converted into electricity through generators

Question 44

what are the pros of hydroelectric dams and tidal barrages

Answer 44

- large amount of energy with no pollution - reliable source of electricity - running costs are fairly low - work on both large and small scales

Question 45

what are the cons of hydroelectric dams and tidal barrages

Answer 45

- sometimes stops boats and fishes from travelling - risk of flood - big impact on the surroundings