Topic 4- Energy

Question 1

What is the law of conservation of energy?

Answer 1

Even energy can neither be created nor destroyed. It can only be transferred from one object to another or from one kind to another.

Question 2

Efficiency equation?

Answer 2

Output/ input

Question 3

What are snakes diagrams and what do they show

Answer 3

Snakes diagrams are diagrams which show the flow of energy. They show how much of the energy has been wasted and how of it has been used.

Question 4

What is conduction?

Answer 4

This is the heat transfer in solids. Particles gain heat energy, making them vibrate about their positions. Because particles are closely arranged, the vibrations are pressed on to other particles from the hot end of the object to the cold end.

Question 5

What is convection ?

Answer 5

This is the heat transfer that takes place in liquids and gases. When particles gain heat energy, they become less dense and rise, taking the place of other molecules that have it been heated. The denser particles fall to the bottom, and they get heated. Eventually, all molecules have been heated as this process is repeated. (Convection current)

Question 6

What is radiation?

Answer 6

This is the transfer of heat through infrared waves. As they do not need particles to vibrate, they can transfer energy through vacuums.

Question 7

How is convection involved in every day phenomena?

Answer 7

Heating in houses: convection currents created by the heater heats the room
Convection currents in the mantle: this causes tectonic plates to move.
Hot drinks: convection currents take place as the hot liquid heats the air, cooling down the liquid.

Question 8

How do people and other objects insulate themselves?

Answer 8

Humans: we wear clothes to prevent heat loss from conduction.
Double glazed Windows: these are filled with air to prevent heat loss by conduction.
Insulating materials: these prevent heat loss by conduction and convection.

Question 9

Equation for work done

Answer 9

Force X distance.

Question 10

Equation for gravitational potential energy?

Answer 10

Mass X g X height.

Question 11

Equation for Kinetic energy?

Answer 11

0.5 X m X v^2

Question 12

Because energy is conserved, how can we relate GPE and KE?

Answer 12

0.5mv^2 = mgh

Question 13

What is power?

Answer 13

Power is the rate of transfer of energy/work.

Question 14

How do you calculate power

Answer 14

Work done/ time.

Question 15

How can we produce energy by wind?

Answer 15

KE energy from the wind turns a turbine, which turns a generator. This then produces electricity.

Question 16

How does water produce electricity?

Answer 16

Kinetic Energy from the water turns a turbine, which turns a generator and therefore produces electricity.

Question 17

How is electricity produced by geothermal resources?

Answer 17

Thermal energy from the location heats water into steam. This steam is then used to turn a turbine, which turns a generator and produces electricity.

Question 18

How is energy produced from solar heating systems?

Answer 18

Light energy from the sun is used to heat water for baths, showers and swimming pools.

Question 19

How can solar cells be used to produce electricity?

Answer 19

Light radiation from the sun gives out heat and electricity.

Question 20

How can fossil fuels be used to produce electricity?

Answer 20

Heat energy from the fossil fuel when it is burnt can be used to heat water into steam. The steam then turns a turbine, which turns a generator= electricity

Question 21

How can nuclear power be used to produce electricity?

Answer 21

Kinetic energy from a radioactive particle heats a coolant. The coolant is then used to heat water into steam. The steam turns a turbine, which turns a generator= electricity.

Question 22

What are the advantages and disadvantages of wind power?

Answer 22

\+= no renewable costs, no waste gases and once set up,mlittle maintenance is required. 
-= expensive to set up, noisy, ugly and unreliable as it is not always windy.

Question 23

What are the advantages and disadvantages of water energy?

Answer 23

\+= renewable, no waste gases, produces a lot of energy. 
-= a lot of notice is produced and dams are destructive as they can flood areas.

Question 24

What are the advantages and disadvantages of geothermal energy?

Answer 24

\+= virtually emission free, easy to maintain, no fuel costs and not a lot of CO2 is produced. 
-= expensive and can only work in areas where geothermal activity is high.

Question 25

What are the advantages and disadvantages of solar heating systems?

Answer 25

\+= renewable, no CO2 produced, and no fuel costs. 
-= unreliable, expensive and inefficient

Question 26

What are the advantages and disadvantages of solar cells?

Answer 26

\+= renewable, no CO2 produced or pillion, no fuel cost 
-= unreliable, expensive and inefficient

Question 27

What are the advantages and disadvantages of using fossil fuels to make energy

Answer 27

\+= cheap, portable and can be built anywhere 
-= non-renewable, produces greenhouse gases and leaks are dangerous and expensive to get rid of.

Question 28

What are the advantages and disadvantages of nuclear power?

Answer 28

\+= reliable, no CO2 produced and we basically have an infinite supply. 
-= expensive, produces radioactive waste and is dangerous in terms of leaks and terrorism.