Current Electricity Overview
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Questions and Answers

What distinguishes primary cells from secondary cells?

  • Secondary cells are used in fuel cells.
  • Primary cells can be recharged.
  • Secondary cells cannot be recharged.
  • Primary cells cannot be recharged. (correct)

Fuel cells produce toxic gases as a byproduct.

False (B)

What is the main function of a hydro-electric generating station?

To convert the energy of falling water into electrical energy.

The top of the battery is the ______ terminal.

<p>positive</p> Signup and view all the answers

Match the following renewable energy sources with their description:

<p>Hydro-electric = Uses falling water to generate electricity Tidal = Uses the movement of ocean tides to generate electricity Wind = Uses wind to turn turbines for electricity Geothermal = Uses heat from the earth's core to generate electricity</p> Signup and view all the answers

Which statement is true about secondary cells?

<p>They can be recharged and reused. (D)</p> Signup and view all the answers

Electricity can only be produced from renewable energy sources.

<p>False (B)</p> Signup and view all the answers

What is one disadvantage of hydro-electric power generation?

<p>It can damage the ecosystem by flooding.</p> Signup and view all the answers

A wind turbine consists of large blades mounted on a ______.

<p>tower</p> Signup and view all the answers

What is the role of a turbine in electricity generation?

<p>To convert mechanical energy into electrical energy. (D)</p> Signup and view all the answers

What is a disadvantage of wind energy?

<p>Wind isn't always blowing (D)</p> Signup and view all the answers

Solar energy is less than 30% efficient.

<p>True (A)</p> Signup and view all the answers

What is one way geothermal energy can be utilized?

<p>Heating or cooling buildings</p> Signup and view all the answers

Biomass generation relies on organic materials such as ______.

<p>wood</p> Signup and view all the answers

Match the energy source with its characteristic:

<p>Wind Energy = Can power 250 Canadian homes Solar Energy = Photovoltaic cells convert light Geothermal Energy = Uses heat from the Earth Fossil Fuels = Non-renewable energy source</p> Signup and view all the answers

Which of the following is a benefit of using biomass generation?

<p>Organic material is available everywhere (D)</p> Signup and view all the answers

Nuclear power is a renewable energy source.

<p>False (B)</p> Signup and view all the answers

What greenhouse gases are produced from biomass generation?

<p>Methane and CO₂</p> Signup and view all the answers

Thermal generation involves heating water to produce ______.

<p>steam</p> Signup and view all the answers

Which energy source has the potential to pollute air and water less?

<p>Solar Energy (D)</p> Signup and view all the answers

What is the main characteristic of direct current (DC)?

<p>Electrons flow in one direction only (B)</p> Signup and view all the answers

Alternating current (AC) is more efficient for distributing electrical energy over long distances than direct current (DC).

<p>True (A)</p> Signup and view all the answers

Name one component of an electric circuit.

<p>Energy Source, Load, Conducting Wires, or Switch</p> Signup and view all the answers

An open circuit occurs when the switch is ______.

<p>off</p> Signup and view all the answers

Match the following types of electricity with their correct definitions:

<p>Direct Current (DC) = Flow of electrons in one direction Alternating Current (AC) = Flow of electrons that alternates direction</p> Signup and view all the answers

Which of the following is an example of a load in an electric circuit?

<p>Lamp (A)</p> Signup and view all the answers

Electric cells convert electrical energy into chemical energy.

<p>False (B)</p> Signup and view all the answers

What are conducting wires used for in an electric circuit?

<p>To provide a path for electrons to flow.</p> Signup and view all the answers

Electricity is produced through the flow of ______ in an electric circuit.

<p>electrons</p> Signup and view all the answers

What happens in a closed circuit?

<p>Electricity can flow (D)</p> Signup and view all the answers

Which of the following is a pro of nuclear energy?

<p>It doesn't emit greenhouse gases. (C)</p> Signup and view all the answers

Uranium is a renewable energy resource.

<p>False (B)</p> Signup and view all the answers

What is the formula used to calculate percent efficiency?

<p>percent efficiency = (E_out / E_in) × 100%</p> Signup and view all the answers

A 60 W light bulb operating for one year costs approximately __________.

<p>$14.37</p> Signup and view all the answers

Match the units of measurement with their descriptions:

<p>Watt (W) = Unit of electrical power Watt-hour = Energy consumed by one watt for one hour Kilowatt-hour (kWh) = Energy consumed by one thousand watts for one hour Efficiency = Ratio of useful energy output to energy input</p> Signup and view all the answers

What is the effect of operating an electrical appliance on weekdays from 7 AM to 7 PM in Ontario?

<p>It is more expensive. (D)</p> Signup and view all the answers

A kilowatt-hour is equivalent to 100 watts of energy used for one hour.

<p>False (B)</p> Signup and view all the answers

How much energy does an older clothes dryer typically consume compared to a newer model?

<p>Older models consume 800 kWh, while newer ones consume 300 kWh.</p> Signup and view all the answers

The cost to operate an electrical device can be calculated using the equation: __________.

<p>COST TO OPERATE = power used (kW) × time (hours) × cost of electricity</p> Signup and view all the answers

What is a significant environmental concern related to nuclear energy?

<p>Nuclear waste storage and radioactivity. (A)</p> Signup and view all the answers

Flashcards

Current Electricity

Electric charges flowing through a conductor in a controlled way.

Direct Current (DC)

Electron flow in one direction through a circuit.

Alternating Current (AC)

Electron flow that reverses direction through a circuit.

Electric Circuit

A closed path for electron flow.

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Energy Source

Provides the energy for electron flow in a circuit, like a battery or power plant.

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Load

Device that uses electrical energy, transforming it into another form.

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Conducting Wires

Provide a path for electrons in a circuit.

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Closed Circuit

A complete circuit, allowing electricity to flow.

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Open Circuit

An incomplete circuit, preventing electricity from flowing.

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Electric Cell

A portable device converting chemical energy into electrical energy.

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Primary Cell

A type of electric cell that cannot be recharged.

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Secondary Cell

A rechargeable electric cell that can be reused many times.

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Battery

Two or more electric cells combined.

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Fuel Cell

A type of electric cell with a continuous chemical supply.

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Hydro-Electric Generation

Generating electricity using falling water.

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Tidal Generation

Generating electricity using the movement of ocean tides.

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Wind Turbine

Large blades mounted on a tall tower that generate electricity from wind.

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Electricity Generation

Converting one type of energy into electrical energy.

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Renewable Resource (Water)

Natural resource that replenishes naturally and will never run out (water for hydro-electric).

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Renewable Resource (Wind)

Natural resource that continues to be available without being used up (wind).

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Wind Turbine Power

Wind turbines use wind energy to generate electricity.

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Solar Panel Energy

Solar panels convert sunlight directly to electricity.

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Geothermal Energy

Uses Earth's heat to generate energy; often uses steam.

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Biomass Energy

Uses plant or animal matter to create energy.

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Non-renewable Energy

Energy sources that will eventually run out.

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Thermal Generation

Using heat to create electricity, often with steam.

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Fossil Fuels

Coal, oil, and natural gas; non-renewable energy sources.

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Nuclear Power

Energy from splitting atoms; creates heat for the electricity.

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Wind Turbine Pros

Located near power use, doesn't pollute air/water.

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Solar Panel Cons

Low efficiency, expensive, limited sunlight hours.

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Electrical Efficiency

A measure of how much useful energy a device produces relative to the energy supplied.

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Energy Efficiency

A measure of how much useful energy is produced compared to the input energy.

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Kilowatt-hour (kWh)

A unit of energy; 1000 watts used for one hour.

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Electrical Power (P)

The rate at which electrical energy is used or produced.

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Cost of Electricity

The price per unit of electrical energy (e.g., kWh).

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Efficiency Formula

Efficiency = (Energy out / Energy in) * 100%.

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Nuclear Energy

Energy released from nuclear reactions (fission).

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Nuclear Waste

Radioactive materials produced during nuclear reactions.

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Cost to Operate

Calculated by multiplying power (kW) by time (hours) and cost per kWh.

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Watt

The unit of electrical power. Measured how much energy is used or produced in a second.

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Study Notes

Current Electricity

  • Current electricity is the controlled flow of electric charges (electrons) through a conductor, like copper or aluminum wires.
  • This flow can be provided from batteries or electrical generating stations.
  • Electronic devices require electron flow to operate.
  • This continuous electron flow path is called an electric circuit.

Two Forms of Current Electricity

Direct Current (DC)

  • A flow of electrons in one direction through an electric circuit.
  • Produced by an electric cell, powering small devices.

Alternating Current (AC)

  • A flow of electrons that alternates in direction through an electric circuit.
  • Produced by generating stations (like wall outlets) to power lights and large devices.
  • More efficient than DC for distributing electrical energy over long distances.

Electric Circuits

  • Electric circuits are like circulatory systems, with electrons flowing around completing a loop.
  • Four key components are always included:
    • Energy source (e.g., battery, generating station)
    • A load (device that changes electrical energy to another form, e.g., heater, light bulb)
    • Conducting wires (connect the other parts)
    • A switch (controls the ciruit flow, sometimes)
  • Open circuit: switch is off, no electricity flows.
  • Closed circuit: switch is on, electricity flows.

Electrical Energy Sources

Electric Cells

  • Convert chemical energy into electrical energy.
  • Have a positive and negative terminal, used in portable devices.
  • Primary cells cannot be recharged, and secondary cells can be recharged.
  • All batteries are toxic to the environment and should be properly recycled.

Fuel Cells

  • Special type of electric cell with continuous chemical supply.
  • Can operate much longer than conventional electric cells, converting chemicals (e.g., hydrogen, oxygen) to electrical energy, which usually creates harmless water as a byproduct.

Generating Electricity

  • Electricity is created by converting one type of energy (often mechanical) into electrical energy.
  • Generating stations use external force (like water, wind) to turn turbines.
  • Inside the turbine, a wire coil turns near a magnet, generating the electron flow.
  • This energy can be transported long distances.

Generating Using Renewable Sources

Water Generation (Hydropower)

  • Uses the energy of falling water to turn turbines.
  • Waterfalls and reservoirs can generate electricity.
  • A renewable resource that replenishes continuously.
  • Pros: environmentally friendly (no pollution)
  • Cons: needs suitable locations, large resource needs, ecosystem disruption (e.g., flooding).

Tidal Generation

  • Uses the cyclical movement of tides.
  • Generates electricity using tides coming and going.
  • Only suitable locations near coastlines with large tides.
  • Pros: does not pollute the environment
  • Cons: Only works in specific geographical locations

Wind Generation

  • Large blades mounted on tall towers utilize wind to generate electricity.
  • Turbines are connected to generators to convert the wind's energy into electricity.
  • Pros: Convenient locations, doesn't pollute the environment.
  • Cons: Wind availability is unpredictable; not always blowing.

Solar Generation

  • Photovoltaic cells directly convert light into electricity.
  • The Sun's energy is constantly available worldwide (a renewable resource.)
  • Pros: clean energy; can work independently of the power grid
  • Cons: lower efficiency than other methods and expensive.

Geothermal Generation

  • Uses heat from the Earth's crust to generate steam to turn turbines.
  • The ground maintains a relative temperature and is a source of power.
  • Pros: constant, readily available heat (temperature) source
  • Cons: Very expensive and expensive to set up.

Biomass Generation

  • Uses plant or animal matter to generate energy through various methods.
  • A renewable resource because vegetation replenishes itself, though not for coal or other fuels.
  • Pros: readily available; renewable
  • Cons: Creates green house gases (methane and CO2)

Generating Using Non-Renewable Sources

Thermal Generation

  • Uses heat (from any source) to turn water into steam and use the steam pressure to turn turbines generating electricity.
  • Includes fossil fuels, nuclear power, etc.

Fossil Fuels

  • Coal, oil, and natural gases generate significant amounts of heat.
  • A non-renewable energy source, because the supply is limited.
  • Pros: creates large amounts of energy
  • Cons: Burning produces CO2 and other toxic chemicals, contributing to environmental problems.

Nuclear Power

  • Uranium atoms split in nuclear reactors to release large amounts of heat.
  • A non-renewable energy source, limited supply of uranium.
  • Pros: High energy output, no greenhouse gas emissions
  • Cons: Radioactive waste disposal is a significant environmental concern.

Electrical Power and Efficiency

  • Electrical power (P) is the rate at which electrical energy is produced or consumed over time. Unit of measure: watt (W).
  • Efficiency is a comparison of useful energy to total energy. (energy out/energy in * 100%).
  • Not all devices use energy efficiently.
  • Some appliances produce more heat and less usable light.

Cost of Electricity

  • Electricity prices vary by time of day (peak or off-peak) and day of the week.

Energuide and Energy Star Labels

  • Labels provide estimates of appliance's annual energy consumption.
  • "Phantom load" refers to small amounts of energy used by appliances when off but still plugged in.

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Related Documents

Current Electricity PDF

Description

This quiz covers the essentials of current electricity, focusing on direct current (DC) and alternating current (AC). It explores how these forms of electricity are generated and their applications in modern devices. Understand the role of electric circuits and their components in facilitating the flow of electrons.

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