energy

Question 1

what are the energy stores?

Answer 1

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

Question 2

how is energy transferred?

Answer 2

• mechanically
• electrically
• heating
• radiation

Question 3

what is work done?

Answer 3

energy transfer

Question 4

what is the equation for kinetic energy?

Answer 4

kinetic energy = 1/2mv^2

Question 5

what is the equation for gravitation potential energy?

Answer 5

GPE = m x gravitational field strength (N/kg) x h

Question 6

what is the equation for elastic potential energy ?

Answer 6

EPE = 1/2 x spring constant x extenstion^2

Question 7

what is specific heat capacity ?

Answer 7

-how hard it is to heat something up

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

Question 8

what is the equation for change in thermal energy?

Answer 8

change in thermal energy= m x specific heat capacity (j/kg) x temperature change

Question 9

how do you investigate specific heat capacities?

Answer 9

• block of material with 2 holes, one for heater and one for thermometer
• measure mass of block
• insulate to reduce energy transfer
• measure initial temperature
• set power supply to 10 V and start stopwatch
• note temperature every minute (current SHOULD NOT change )
• 10 reading then turn of power supply
• use equation to find specific heat capacity

Question 10

what is the equation for power?

Answer 10

power = energy transfer / time 
OR 
power = work done / time 
OR 
power = I^2 x R

Question 11

what is the conservation of energy principle ?

Answer 11

energy CAN be transferred but can NEVER be created or destroyed

Question 12

what does dissipated energy mean ?

Answer 12

wasted energy

Question 13

what is power measured in ?

Answer 13

WATTS

Question 14

what does one watt equal =

Answer 14

1 joule of energy transferred per second

Question 15

what is conduction?

Answer 15

conduction = is the process where vibrating particles transfer to neighbouring particles

Question 16

what energy store is heating?

Answer 16

THERMAL STORE

Question 17

what is thermal conductivity?

Answer 17

a measure of how quickly energy is transferred through a material . High thermal conductivity means there is quick transfer of energy between particles .

Question 18

what is convection?

Answer 18

convection is where energetic particles move AWAY from HOTTER TO COOLER

• only in LIQUIDS and GASSES

Question 19

what happens when you heat a gas or liquid?

Answer 19

as particles can move, the space between the particles increase, causes density to decrease

Question 20

how can a house be insulated ?

Answer 20

• thicker/ cavity walls
• thermal insulation
• loft insulation eg. fibreglass wool
• double glazed windows

Question 21

how can you investigate the effectiveness of insulators ?

Answer 21

• boil water in a kettle in a sealable container and measure mass
• measure initial temperature
• seal container and wait 5 minutes
• remove lid and measure final temperature
• repeat with a different material wrapped around the container

Question 22

what is the equation for efficiency?

Answer 22

useful output / total input

Question 23

what is one of the only devices that can be 100% efficient?

Answer 23

an electric heater

Question 24

how is energy wasted ?

Answer 24

HEAT

SOUND

Question 25

what are the three main fossil fuels ?

Answer 25

- coal - oil - gas (natural)

Question 26

what is a finite resource?

Answer 26

- they will run out - damage the environment - provide most of our energy

Question 27

what is are some examples of renewable energy?

Answer 27

- solar - wind - hydro electric - geothermal - tides

Question 28

what is renewable energy?

Answer 28

- never runs out - less damage to the environment than fossil fuels - can be unreliable

Question 29

what non-renewable energy resources are used for transport?

Answer 29

- PETROL and DIESEL ----> cars | - COAL ---->trains

Question 30

what is a renewable energy resource for vehicles?

Answer 30

BIO FUELS

Question 31

positives and negatives for wind turbines?

Answer 31

``` + no pollution minimum running cost no permanent damage to the landscape - 1500 turbines = one coal-fired power station noisy spoils the view ```

Question 32

what is a bio fuel made from?

Answer 32

PLANTS and WASTE solid or liquid or gas it can be burnt to produce electricity used in the same ways as fossil fuels

Question 33

what are the positive aspects of bio-fuels?

Answer 33

- carbon neutral IF plants are being grown at the same rate as burning - reliable

Question 34

what are the negative aspects of bio-fuels?

Answer 34

- can't respond to immediate demand - takes up space and water that could be used to grow food - needs a lot of space that has lead to some deforestation and destruction of animals habitats .

Question 35

how does fossil fuels impact the environment?

Answer 35

- burning them release carbon dioxide which adds the greenhouse effect and contributes to global warming - burning coal and oil releases sulfur oxide which causes acid rain