energy resources and energy transfer

Question 1

describe the process of conduction

Answer 1

thermal conduction is the process where vibrating particles transfer energy from their kinetic energy store to the kinetic energy store of neighbouring particles.
- occurs mainly in solids

Question 2

describe the process of convection

Answer 2

convection occurs when the more energetic particles move from the hotter region to the cooler region- and transfer energy as they do
eg in an immersion heater:
1)water is heated
2) less dense water rises
3) fast moving particles collide with slower ones and transfer energy
4) water cools and becomes more dense
5) denser water sinks

Question 3

describe the process of radiation

Answer 3

the emission of electromagnetic waves

1) hotter objects emit more radiation
2) cooler objects absorb more radiation
3) black surfaces absorb/emit more radiation than white
4) matt surfaces are better at absorbing and emitting radiation than shiny surfaces

Question 4

explain the process of insulation

Answer 4

clothes, blankets and foam are all insulators

• they trap pockets of air
• the air cant move very well so the the energy is transfered very slowly through the pockets of air and the material between because they have a low thermal conductivity

Question 5

what are the 8 different energy stores

Answer 5

kinetic ( anything moving)
thermal (amount of heat energy)
chemical (eg fuel)
gravitational potential (anything which can fall)
elastic potential ( anything stretched)
electrostatic 
magnetic
nuclear

Question 6

4 ways of transferring energy

Answer 6

mechanically: an object moving due to a force
electrically: a charge moving through a potential difference
by heating: energy transferred from hot to cold objects
by radiation: energy transferred by light/ sound waves

Question 7

what is the efficiency of an energy transfer

Answer 7

useful energy output/ total energy output x 100

Question 8

how to investigate the emission of thermal radiation

Answer 8

use a leslie cube
fill will boiling water
put an infrared detector and measure which side emits the most

Question 9

what is work done

Answer 9

energy transferred

Question 10

what is the equation for work done

Answer 10

force x distance moved

Question 11

what is power

Answer 11

power = work done/ time taken

Question 12

what is the equation for GPE

Answer 12

GPE= mgh

Question 13

what is the equation for kinetic energy

Answer 13

KE = 1/2 m v2

Question 14

what is absolute zero

Answer 14

the temperature at which the particles have as little energy as possible
-273 degrees Celsius
0 kelvins

Question 15

how to convert from Celsius to kelvin

Answer 15

add 273

Question 16

what is the relationship between kinetic energy stores and temperature

Answer 16

the temperature of a gas is proportional to the average energy in the kinetic energy stores

Question 17

explain how colliding gas particles creates pressure

Answer 17

when gas particles collide with something they exert a force
in a sealed container the particles collide with the sides, exerting a force over an area (ie pressure)

Question 18

what is the relationship between pressure and volume

Answer 18

p1V1 = p2V2
(Pressure x volume = constant)

** at constant temp

Question 19

what is the relationship between pressure and temperature

Answer 19

p1/T1 = p2/T2

** at constant volume