1-Energy

Question 1

What does a system mean

Answer 1

A single object or group of objects that you r interested in

Question 2

What happens when a system changes

Answer 2

Energy is transferred

Question 3

What is a closed system

Answer 3

Neither matter or energy can enter or leave

Question 4

How can energy be transferred

Answer 4

Heating
Doing work
Radiation
Electrically

Question 5

What is the equation for kinetic energy

Answer 5

Kinetic energy(J) =1/2mass(Kg) x speed2 (m/s)2

Ek = 1/2mv*2

Question 6

What is the equation for gravitational potential energy

Answer 6

g.p.e(J) = Mass(kg) x gravitational field strength (N/kg) x Height(m)

Ep = mgh

Question 7

When there is no air resistance, what happens to a falling object’s energy stores

Answer 7

Energy lost from g.p.e store =

Energy gained in the kinetic energy store

Question 8

What is the equation for elastic potential energy

Answer 8

Elastic potential energy(J) = 1/2 x spring constant (N/m) x extension*2(m)

Ee = 1/2ke*2

Question 9

What is specific heat capacity

Answer 9

The amount of energy need to raise the temperature of 1kg of a substance by 1°C

Question 10

What is the equation that links change in thermal energy to specific heat capacity

Answer 10

Change in thermal energy(J) = Mass(kg) x specific heat capacity(J/kg°C) x Temperature change(°C)

^E = mc^Ø

Question 11

What is the conservation of energy principle

Answer 11

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

Question 12

What is the power equation linking to energy transferred

Answer 12

Power(W) = Energy transferred(J) / Time (s)

P=E/t

Question 13

What is the power equation linking to work done

Answer 13

Power(W) = Work done(J) / Time (s)

P=W/t

Question 14

What is conduction

Answer 14

The process where vibrating particles transfer energy to neighbouring particles

Question 15

What is thermal conductivity a measure of

Answer 15

How quickly energy is transferred through a material through conduction

Question 16

What is convection

Answer 16

Where energetic particles move away from hotter to cooler regions

Question 17

What can convection go through

Answer 17

Gases and liquids because their particles can move

Question 18

What can be used to reduce frictional force

Answer 18

Lubricants, like oil

Question 19

What are some examples of thermal insulation used in housing

Answer 19

Cavity wall insulation,
Loft insulation,
Double glazed windows,
Draught excluders

Question 20

How can the effectiveness of materials as thermal insulators be measured

Answer 20

Fill a sealable container with boiled water and record starting temp,
Wrap beaker in different materials a leave it for 5minutes each time,
Measure final temperature,
The lower the temperature change, the better the insulator

Question 21

How can u calculate the efficiency for a energy transfer

Answer 21

Efficiency =

Useful output energy transfer / total input energy transfer

Question 22

How can efficiency of a device in terms of power be calculated

Answer 22

Efficiency =

Useful power output / total power input

Question 23

Examples of non renewable energy resources

Answer 23

Coal
Oil
Natural gas
Nuclear

Question 24

Examples of renewable energy resources

Answer 24

Solar
Wind
Bio-fuel
Hydro-electricity 
Geothermal 
Tidal
Water waves

Question 25

How do wind turbines work

Answer 25

Each turbine has a generator inside and the rotating blades turn the generator

Question 26

What are advantages or wind turbines

Answer 26

Very little pollution (only in manufacture) No permanent damage to environment No fuel costs Minimal running costs

Question 27

What are disadvantages or wind turbines

Answer 27

``` Spoil views, Can be very noisy, Don’t work if wind stops, Impossible to increase supply if there is extra demand, Initial costs r high ```

Question 28

Advantages of solar cells

Answer 28

Can be used in remote areas Little pollution (only in manufacture) Very reliable source in sunny countries Very small running costs

Question 29

Disadvantages of solar cells

Answer 29

Can’t increase power output when there is extra demand Initial costs are high Generate electricity on a relatively small scale

Question 30

Advantages of geothermal energy

Answer 30

Reliable Very little damage to environment Can be used to generate electricity or heat homes directly

Question 31

Disadvantages of geothermal

Answer 31

Not very many suitable locations | Cost of building a power plant is high compared to energy output

Question 32

Advantages of hydro-electricity

Answer 32

Can provide an immediate response to an increased demand for electricity Reliable No fuel costs Minimal running costs

Question 33

Disadvantages of hydro-electricity

Answer 33

Big impact on environment due to the flooding of the valley Ugly when the reservoirs dry up Initial costs r high

Question 34

Advantages of wave power

Answer 34

No fuel costs Minimal running costs Useful in small islands

Question 35

Disadvantages of wave power

Answer 35

``` Disturbs the seabed Spoils the view Hazard for boats Fairly unreliable since the waves die out when wind stops Initial costs are high ```

Question 36

How do tidal barrages work

Answer 36

Big dams built across river estuaries with turbines in them. As the tide comes in, it fills up the estuary and then the water is allowed out through turbines at a controlled speed

Question 37

Advantages of tidal barrages

Answer 37

No pollution Pretty reliable as the tide comes in twice a day No fuel costs Minimal running costs Potential for generating a significant amount of energy

Question 38

Disadvantages of tidal barrages

Answer 38

``` Prevent free access by boats Spoils view Alters habitat Smaller tides will produce significantly less energy than bigger ones Initial cost is high ```

Question 39

How do biofuels work

Answer 39

Plant products or animal dung is burnt to produce electricity

Question 40

Advantages of biofuels

Answer 40

Fairly reliable as crops take a relatively short time to grow Supposedly carbon neutral but some debate over it

Question 41

Disadvantages of biofuels

Answer 41

Cost to refine biofuels is very high Large areas of forest have been cleared to make room to grow biofuels Worry that crops specifically grown for biofuels leave no space or water for food crops

Question 42

Advantages of non-renewable power

Answer 42

``` Reliable Power plants can respond to changes in demand Low running costs Fairly low fuel extraction costs Cost effective ```

Question 43

What r the impacts of fossil fuels on the environment

Answer 43

Release lots CO2 into environment Releases sulfur dioxide- acid rain Coal mining destroys habitats Oil spillages affect mammals and birds in that area

Question 44

What r the disadvantages of nuclear power

Answer 44

Nuclear waste is difficult and dangerous to dispose of Overall cost is high Risk of catastrophes

Question 45

Why r more renewable energy resources being used

Answer 45

People and government r becoming increasingly aware that non-renewables will run out, Government set targets and put pressure on energy providers Ethical and moral reasons Electric and hybrid cars r increasing in popularity

Question 46

How does money limit the use of renewables

Answer 46

Building new power plants is expensive so energy providers r reluctant to do this The cost of switching will have to be paid either by customers in their bills or through taxes New products like cars a expensive for customers

Question 47

How does politics affect the use of renewables

Answer 47

People don’t want to live next to a power station and there r arguments over whether forcing them is ethical

Question 48

How does reliability limit the use of renewables

Answer 48

Some, like wind, are not as reliable as fossil fuels and others can not increase power on demand.