Energy

Question 1

What is elastic energy?

Answer 1

Elastic potential energy is stored when an object is stretched or squashed eg. compressed springs, inflated balloons.

Question 2

What is kinetic energy?

Answer 2

Kinetic energy is the energy of a moving object. Eg. Runner, Buses.

Question 3

What is thermal energy?

Answer 3

• The total kinetic and potential energy of particles in an object.
• This is in the vibrations of the object - Kinetic energy.
• Increasing separation of molecules requires work to be done by the potential energy store.
• In hotter objects, they have more thermal energy and vibrate faster.

Question 4

What is chemical energy?

Answer 4

• Energy stored in chemical bonds.

- Can release energy by a chemical reaction. Eg. Food, Fuels, Batteries.

Question 5

What is nuclear energy?

Answer 5

• Energy stored in the nucleus of an atom.

Question 6

What is electrostatic energy?

Answer 6

• Energy sored when repelling charges move closer together or when attracting charges are pulled further apart.

Question 7

What is magnetic energy?

Answer 7

• Energy stored when repelling poles are pushed closer together and attracting poles move further apart. eg. a fridge magnet, maglev trains.

Question 8

What is mechanical work?

Answer 8

• Mechanical work is a force moving an object through a distance.

Question 9

What is electric work?

Answer 9

• Electric work is when charges are moving due to a potential difference.

Question 10

What is voltage?

Answer 10

• Voltage is the measure of energy given to charge carriers.

Question 11

What is potential difference?

Answer 11

• Potential difference is the voltage between two points that make an electric current flow.

Question 12

What is heating?

Answer 12

• Heating is an energy transfer due to temperature difference caused electrically or by a chemical reaction.

Question 13

What is radiation?

Answer 13

• Radiation is energy transferred by waves. eg. light, infrared radiation emitted from the sun.

Question 14

What are energy flow diagrams?

Answer 14

• Energy flow diagrams show how energy is transferred from one store to another.

Question 15

What is work?

Answer 15

• Work is the measure of energy transfer when a force moves an object through a distance.

Question 16

What are work done and energy transferred measured in ?

Answer 16

• Work done and energy transferred are measured in Joules.

Question 17

What is power?

Answer 17

• Power is the rate energy is transferred per second.

Question 18

What is the equation for work done?

Answer 18

• Word done = force x distance

Question 19

What is the equation for power?

Answer 19

• power = work done/ time

Question 20

What is efficiency?

Answer 20

Efficiency: How good a device is at transferring energy input to useful energy output.

Question 21

What is the equation of efficiency?

Answer 21

Efficiency = useful energy transferred/ total energy supplied x 100 .

Question 22

How many milijoules are in a joule?

Answer 22

• A millijoule is 0.001J. so 1/1000 of a Joule.

Question 23

How many kilojoules are in a joule?

Answer 23

• 1000J in a kilojoule.

Question 24

What is “The Law of the Conservation of energy?”

Answer 24

• The Law of Conservation means that the total energy before transfer is the same as the total energy after transfer because it cannot be created/ destroyed.

Question 25

Who is the "Joule" named after?

Answer 25

- The Joule is named after James Prescott Joule (scientist.)

Question 26

Give two examples of energy transfer diagrams.

Answer 26

- Transfer diagram. | - Sankey diagram.

Question 27

What does it mean if energy is dissipated?

Answer 27

- Dissipation is the transfer of energy stores into less useful ones. Known as "wasted" energy.

Question 28

Why is a lubricant used?

Answer 28

- Lubricants are used to reduce the amount of friction, therefore decreasing the thermal energy. - Energy will not be dissipated.

Question 29

Why are LED lights more efficient than filament lights?

Answer 29

- They are energy efficient, producing less heat (dissipated energy.)

Question 30

Give an example of energy dissipation.

Answer 30

- Electrical work in tumble dryers. - Transferred to useful thermal energy. - Dissipated into sound waves

Question 31

What is the calculation for the amount of kinetic energy?

Answer 31

Kinetic energy = 1/2x mass x speed (squared)

Question 32

When using the formula for kinetic energy, what is the measure of mass?

Answer 32

- The measure of the mass is Kg.

Question 33

How much kinetic energy does a 30 kg dog have when it runs at 4 m/s?

Answer 33

- 240J

Question 34

What is the formula for the calculation of kinetic energy?

Answer 34

Ek = 1/2mv(squared.)

Question 35

What is a renewable energy source?

Answer 35

- A renewable energy source is one that is being (or can be) replenished as it is used.

Question 36

Give two advantages of renewable energy resources.

Answer 36

- Renewable energy will never run out. | - Once in place, will not add CO2 to atmosphere, not contributing to climate change.

Question 37

Hydroelectric power is very reliable, so what is the issue with it?

Answer 37

- Many habitats are destroyed when building them. | - Only suitable in countries with a lot of rivers, not the UK.

Question 38

What is geothermal energy?

Answer 38

- Geothermal energy is using the heat from the earth to generate electricity.

Question 39

What is a fossil fuel?

Answer 39

- A fossil fuel is a finite resource that releases energy.

Question 40

What is the difference between temperature and thermal energy?

Answer 40

- Temperature is how cold/ hot something is. Depends on how fast particles are moving. - Thermal energy - The more particles (larger it is) more the thermal energy.

Question 41

What is heat?

Answer 41

- Heat is the transfer of thermal energy from a warmer object to a colder object.

Question 42

What is thermal energy affected by and why?

Answer 42

- Mass and size. - Total amount of kinetic + potential energy. - The bigger it is , the more thermal energy it has because it has more particles.