Electrical Principles and Technologies Part Four

Question 1

How does a turbine in a generator work?

Answer 1

It is a shaft with many fan blades. Steam heating blades turns it, rotates large electromagnetic coils in the generator, and produces electricity.

Question 2

How is heat used to generate electricity?

Answer 2

65% of electrical energy is from burning fossil fuels (coal, oil, natural gas). The coal is crushed into a fine powder, blown into a combustion chamber, burned. Boils water and super heats resulting steam. High pressure steam drives large turbine.

Question 3

How is nuclear fission used to generate electricity?

Answer 3

It is the splitting of atoms of a heavy element (uranium), and takes place in a nuclear reactor. The split releases a large amount of energy and is used to produce high-pressure steam for the turbine.

Question 4

How is geothermal energy used to generate energy?

Answer 4

Energy derived from internal heat of the Earth. Hot water and steam heated by hot rocks within Earth’s crust. Steam channeled through pipes used to drive turbines.

Question 5

How is biomass used to generate electricity?

Answer 5

It is biodegradable waste (agricultural waste, compost) that can be used as an energy source for steam-driven generators.

Question 6

What is cogneration?

Answer 6

Use of waste energy from another process such as heating or generating electricity.

Question 7

How do you use water power to generate electricity?

Answer 7

20% of electricity is from hydro-electric power plants. Plants capture energy of falling water. Most use a dam across a river to store water. Water is then directed through a channel (penstock) to a turbine.

Question 8

How do ocean tides generate electricity?

Answer 8

Moving water from tides powers turbines that run generators.

Question 9

How does wind energy generate electricity?

Answer 9

It can be harnessed to turn a shaft. Many wind powered generators connected make wind farms to produce even more electricity

Question 10

How do solar cells generate electricity?

Answer 10

They use the photovolatic effect to make electricity.

Question 11

How do fuel cells generate electricity?

Answer 11

They generate electricity directly from a chemical reaction with a fuel (ex.hydrogen).

Question 12

What are non-renewable resources?

Answer 12

Resources that cannot be replaced once used up (ex.coal, oil, natural gas).

Question 13

What are renewable resources?

Answer 13

Can be renewed naturally in relatively short periods of time (ex. solar energy, geothermal energy, trees)

Question 14

What is air pollution?

Answer 14

Burning of fossil fuels results in the release into the atmosphere of many problem-causing substances.

Question 15

What is flyash?

Answer 15

Airborne ash from burning coal. Has small amounts of mercury: poisonous metal that can damage the nervous system.

Question 16

What are some of the most harmful molecules formed from burning coal? What are their affects?

Answer 16

Sulfur Dioxide- causes acid rain
Nitrogen Oxides- causes air pollution
Carbon Dioxide- cause of global warming

Question 17

What is strip mining?

Answer 17

Removes all plants and animals from large areas to mine coal; result in habitat and species destruction.

Question 18

How do Oil and Gas wells cause pollution?

Answer 18

They often give off poisonous gases.

Question 19

How do steam turbines cause pollution?

Answer 19

they often release warm water into nearby lakes and rivers. Increase in water temperature affects marine ecology and can kill fish.

Question 20

How do mines and refineries cause pollution?

Answer 20

The ones that produce nuclear fuel can cause damage through radioactive waste.

Question 21

How do dams, wind farms, solar cell arrays cause pollution?

Answer 21

They can destroy large areas of ecological habitats.

Question 22

How do tidal power plants cause pollution?

Answer 22

They can disrupt the habitat of fish and other marine life.

Question 23

What is sustainability?

Answer 23

Using resources at a rate that can be maintained indefinitely.

Question 24

Benefits of electrical technologies?

Answer 24

• improved our standard of living
• most improvements/inventions made to improve speed, efficiency, conveniance

Question 25

Drawbacks of electrical technologies?

Answer 25

• the more technology there is the more resources needed, sustainability is hard to keep up
• more waste disposal problems
• some countries cannot afford it and leads to isolation and exclusion

Question 26

Computers and information?

Answer 26

• revolutionized things we do like: writing, calculating, communicating
• use binary numbers (0,1) to store and transmit data which led to the digital technology era

Question 27

How does electricty and computers work?

Answer 27

• electric current used in one way or the other in storing/transmitting information
• lasers, electrical pulses, photo-detectors all allow electronic devices to fulfill their duties

Question 28

How does a computer hard drive work?

Answer 28

Uses electrical pulses to record and transmit info, by using an aluminum or glass disk, with a thin layer of magnetic material that spins at 300km/h. Electrical pulse send to an arm with read and write heads

Question 29

What are heads in a hard drive?

Answer 29

Magnetic coils that magnetize spots on the spinning disk.

Question 30

What is reading in a hard drive?

Answer 30

Magnetic spots induce a current in the electromagnetic coil, reproducing 0’s and 1’s in the original signal and are sent to the computer’s processor.

Question 31

What is writing in a hard drive?

Answer 31

Electrical signals are responded from the computer’s processor.