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Help me study for my science test please! :) 1) Describe the processes for generating...

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natalie25948421 | Student, Grade 9 | (Level 2) eNoter

Posted May 23, 2013 at 5:20 PM via web

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Help me study for my science test please! :)

1) Describe the processes for generating electricity using coal and hydropower. Where in each process does energy escape and result in less than 100% efficiency?

2) Describe the efficiency and the pros and cons of water and coal power.

3) Describe the energy transfers and transformations in coal fired and water powered plants.

4) List 8 electricity generation methods by renewable vs. nonrenewable.

5) Explain the difference between renewable and nonrenewable resources.

6) Identify the main resource used in the US, World, and Washington State to generate electricity.

7) Analyze motion vs. gravitational energy and something thrown up in the air, and then falling, and of something rolling down a ramp. What happens to the total energy in the system?

8) List five kinds of kinetic and five kinds of potential energy.

9) Objects with the same charges _______, and opposite charges ______.

10) How are magnets similar to charged objects?

11) A wire with an electric current becomes a ______ and is produced by ________. A magnet moving near a wire produces ________.

12) A generator starts with ________ energy and is surrounded by _______. A magnet moving near a wire produces _______.

13) A generator starts with ______ energy and ends with _______ energy. A motor starts with ________ energy and ends with ______ energy.

14) What are the constraints and criteria? Give examples of each.

15) How do nuclear power plants work? List the pros and cons.

16) Describe how a photovoltaic cell works and some pros and cons of this technology.

17) Describe how a hydrogen fuel cell works and some pros and cons of this technology.

1 Answer | Add Yours

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tjbrewer | Elementary School Teacher | (Level 2) Associate Educator

Posted May 23, 2013 at 8:33 PM (Answer #1)

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1) Hydropower, and Coal Power:

In conventional Coal Power, coal is burned to generate heat.  Most of the heat is used to heat water and turn it into steam.  Some the heat is lost up the smokestack.  The steam builds up pressure then forces its way through a turbine trying to relieve the pressure.  This turns the turbine, and in turn an electric generator.  Some of the steam's heat is lost in this process.  In some generators they just vent the steam, in others they run the steam through a radiator to condense it back to liquid.  In either case, heat that didn't go to the generator is lost.  Everytime heat escaped, efficiency was lost. 

In hydropower, dams are built across particularly steep rivers.  The water is stored in a reservoir behind the dam, and some of the water is allowed to flow into the powerplant.  Inside the plant the water is allowed to descend (using gravity) and then has to flow through a turbine to get to the riverbed below the dam.  The flow of water turns the turbine which in turn rotates a generator.  Not all of the water's kinetic energy gets to the turbine, and inadvertant friction in the generator leads to the generation of heat. 

You will have to post the unrelated questions separately to get them answered, or hope that another educator answers the questions I didn't answer. 

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