8.1 Energy Sources

Question 1

What is a primary energy source?

Answer 1

Source of energy that has not been process in any way.

Question 2

What is a secondary energy source?

Answer 2

Source of energy that has been processed.

Question 3

What is a non renewable energy source?

Answer 3

A finite energy source which is being depleted much faster than it can be produced so it will run out. Non renewable sources include fossil fuels and nuclear fuels.

Question 4

What is a renewable energy source?

Answer 4

This includes solar energy, wind and wave energy at present 12% of energy comes from these sources.

Question 5

What is specific energy?

Answer 5

The amount of energy that can be obtained from a unit mass of fuel. Measured in Jkg^-1

Question 6

What is energy density?

Answer 6

The amount of energy that can be obtained from a unit volume of a fuel. Measured in Jm^-3

Question 7

What is degradation of energy?

Answer 7

Energy while always being conserved becomes less useful meaning that it cannot be used to perform mechanical work. This is called energy degradation.

Question 8

What is a sankey diagram?

Answer 8

A pictorial energy flow block digram showing energy flows using arrows whose widths are proportional to the respective energy transfers.

Question 9

What is the efficiency of a machine?

Answer 9

useful energy out/ total energy in

or

useful power out/total power in

Question 10

How are fossil fuels produced?

Answer 10

By the decomposition of buried animal and plant matter under the combined action of the high pressure of the material on top and bacteria.

Question 11

How much energy is produced via fossil fuels?

Answer 11

86% worldwide.

Question 12

What are the advantages of fossil fuels?

Answer 12

High energy density
Used directly and easily by a variety of engines and devices
]Extensive distribution network in place

Question 13

What are the disadvantages of fossil fuels?

Answer 13

Release of greenhouse gases into the atmosphere
Environmental problems due to leakages along the production distribution line especially with oil
Need for extensive storage facilities.

Question 14

What is the energy transfer when burning fossil fuels, nuclear furled, wind hydroelectric and wave power?

Answer 14

Converted to kinetic when the water moves or thermal energy when the fuel is burnt, which the water or steam rotates a turbine so this converts to kinetic energy in turbines which is connected to generator which converts it to electrical energy.

Question 15

What is energy transfer in photovoltaic cells?

Answer 15

Solar energy to electrical energy.