Energy

Question 1

what are the energy stores?

Answer 1

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

Question 2

what are the energy pathways?

Answer 2

mechanical , electrical , heat , radiation

Question 3

what is thermal conductivity?

Answer 3

a measure of how well a materical conducts energy when it is heated

Question 4

what is energy efficiency?

Answer 4

the amount if energy which is wasted

Question 5

how do power stations work?

Answer 5

fuel is used to heat water which produces steam

Question 6

what are some renewable energy resources?

Answer 6

hydroelectricity, geothermal , tides , sun

Question 7

what is specific heat capacity?

Answer 7

the energy required to raise one kilogram (kg) of the material by one degree Celsius (°C)

Question 8

power

Answer 8

= energy transferred / time

Question 9

kinetic energy

Answer 9

= 0.5 x mass x velocity2

Question 10

gravitational potential energy

Answer 10

= mass x gravitational field strength x height

Question 11

specific heat capacity

Answer 11

heat energy = mass x specific heat capacity x change in temp

Question 12

define power

Answer 12

power is the amount of energy transferred or converted per unit time

Question 13

elastic potential energy

Answer 13

elastic energy = 1/2 x spring constant change in position squared

Question 14

what is the law of the conservation of energy?

Answer 14

the total energy of an isolated system remains constant

Question 15

what is the definition of dissipation of energy?

Answer 15

Any energy that is not transferred to useful energy stores is said to be wasted because it is lost to the surroundings

Question 16

how to reduce unwanted energy transfers??

Answer 16

insulation

Question 17

what does the higher thermal conductivity of a material do

Answer 17

a higher rate of energy transfer by conduction

Question 18

efficiency in terms of power

Answer 18

useful power out / total power in

Question 19

efficiency in terms of energy

Answer 19

usual energy out / total energy in

Question 20

what are the main energy sources available

Answer 20

fossils fuels, nuclear fuel, biofuel, wind, hydroelectricity, geothermal, tides, sun and water waves

Question 21

what is renewable energy and what are some examples?

Answer 21

energy that is collected from resources that will never run out or which are replaced by nature in less than a human lifetime

hydroelectric, wind, solar, tidal, wave, geothermal, biomass

Question 22

how is internal energy effected by changing temperature and changing state?

Answer 22

temperature : particles speed up and gain kinetic energy

changing state : The electrostatic potential energy of the molecules increases, The bonds between molecules break and the molecules move further apart

Question 23

what does work done cause against the frictional forces acting on an object?

Answer 23

a rise in the temperature of the object