Energy

Question 1

Power equation

Answer 1

Time taken

Question 2

What is power measured in

Answer 2

Watts

Question 3

Work done =

Answer 3

Force (n) x distance moved (m) in direction of the force

Question 4

Change in GPE (joules )

Answer 4

= weight x change in veritical height

Question 5

Kinetic energy

Answer 5

0.5 x mass x speed squared

Question 6

What happens when an object is moved by a force

Answer 6

The force does work and energy is transferred

Question 7

If an object travels faster it’s kinetic energy …

Answer 7

Increases

Question 8

The bigger an objects mass

Answer 8

The bigger the kinetic energy

Question 9

Convection takes place in …

Answer 9

Liquids and gasses

Question 10

Why does convection happen

Answer 10

When liquids or gases are heated the particles gain kinetic energy and move around so take up more space which means the density of the hot liquid or gas is less than the cool liquid or gas on top of it. This leads to the hot liquid or gas rising . Cold liquid or gas is drawn into replace the liquid or gas that has risen and is in turn heated :

Question 11

Why does conduction take place

Answer 11

When heat is transferred by particles vibrating more and making neighbouring particles move more

Question 12

What are the best and worst conductors

Answer 12

Solids are the best and gases are the worst but are the best insulator

Question 13

What can thermal radiation do

Answer 13

It’s an electromagnetic wave so can travel through a vacuum as it does not need particles

Question 14

Silvered surfaces are

Answer 14

Good reflectors and bad absorbers / emitters of heat radiation

Question 15

Black surfaces are

Answer 15

Good emitters and absorbers of infra red radiation but bad reflectors

Question 16

What happens when a metal is heated

Answer 16

The electrons move faster and spread throughout the metal and collide with other electrons transferring their energy

Question 17

How can we reduce heat loss

Answer 17

Wasted heat energy wastes money we can use insulators to stop heat energy escaping like trapped air e.g in expanded polystyrene or between the fibres of a wily jumper . Shiny silver surfaces help to reduce heat loss by radiation

Question 18

What can we put on windows and in walls to stop heat loss

Answer 18

Double glazing and cavity wall insulation

Question 19

Why is water a por conductor of heat

Answer 19

Particles are too far apart to pass the heat energy quickly

Question 20

Efficiency equation

Answer 20

Useful energy output
——————– x100
Total energy input

Question 21

A clockwork motor contains

Answer 21

Stored mechanical energy which is turned into kinetic energy when the spring unwinds

Question 22

An electric generator turns

Answer 22

Kinetic energy into electrical energy

Question 23

A rollercoaster free rolling down turns

Answer 23

Potential energy into kinetic energy

Question 24

What can stored energy be turned into

Answer 24

Active energy

Question 25

What is a non renewable energy source

Answer 25

Can't be replaced and will eventually run out and A renewable slice is replaced naturally

Question 26

Wind energy

Answer 26

Wind mills convert kinetic energy if the wind into electrical energy by using wind to turn generator It's renewable but very expensive to set up and few areas r suitable

Question 27

Hydroelectric power

Answer 27

GPE water stored at height at reservoirs and mountain lakes , water gains kinetic energy falling down the hill , water drives turbine which kinetic energy is y into electrical energy by a generator renewable but few area of world suitable can spoil landscape and alter natural habitat

Question 28

Tidal energy

Answer 28

Dam built across estuary harnesses kinetic energy of sea , fast flowing water turns generators as the tide comes in its renewable but expensive to set up and few places in the world are suitable . As tide falls water flows out of estuary and turbines are spun again damages habitats for wildlife

Question 29

Solar power

Answer 29

Light from sun converted into energy by photovoltaic cells or is used as a heat source . Renewable no CO2 but requires continuous sunshine and cell does not produce a lot of electricity needs bright sunlight and expensive

Question 30

Nuclear energy

Answer 30

Radioactive materials naturally release heat its non renewable and radioactive waste is hard to store and small amounts of nuclear fuel gives large amounts of energy Isotope of uranium needed Power stations expensive to build Releases no greenhouse gases

Question 31

Geothermal energy

Answer 31

Water heated by earths hot rocks can drive turbines to generate electricity or used for domestic heating by being piped to houses its renewable large quantities of energy available but it requires deep drilling and expensive . Also geysers and springs give readily available geothermally heated water

Question 32

Biomass energy

Answer 32

Plants used to make alchahol which is used as Petrol its renewable but requires huge amounts of land to grow plants

Question 33

solar heating

Answer 33

Focusing mirrors focus heat radiation can heat water for high pressure steam production which drives turbines which drive geenarator . Solar heating panels used for water heating absorb thermal radiation

Question 34

Fossil fuels

Answer 34

Non renewable produces greenhouse gases

Question 35

What is electricity and how's it generated

Answer 35

Not an energy resource generated in power stations by this : Stored energy in form of burning fossil or nuclear energy is used to heat water , heat energy in high pressure steam drives turbine this movement energy of rotating turbine spins generator giving electrical output. Energy .

Question 36

Why are we searching for alternate energy forms

Answer 36

Demand for fuel and worries about global warming and pollution

Question 37

Wave energy

Answer 37

Rising water pushes air past turbine spinning turbine drives generator . Falling water sucks air back past turbine making it spin again Clean eentgy source no greenhouse gases

Question 38

What do different types of powers station need to be able to do

Answer 38

Need to be able to respond to changes in demand for electricity . Different types differ in speed which they can meet electricity demand which varies sometimes unpredictably . Nuclear power stations can't be turned on instantly , process of starting reaction and heating up the reactor is lengthy so it can't meet sudden variations in demand . Fossil fuels can be started more quickly but still take hours to start producing electricity . Gas fired ones can respond quicker than coal . Hydroelectric power can respond quickly as they can operate in reverse using surplus electricity to pump water back up to high level reservoirs converting electrical energy into GPE Wind and tidal power r unpredictable