Electric Cells Overview

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Questions and Answers

What occurs at the anode of an electric cell?

Oxidation occurs (correct)

Chemical reactions create ions

Electrons are released

Reduction takes place

Which type of electric cell is designed for one-time use and is not rechargeable?

Alkaline battery (correct)

Lithium-ion cell

Lead-acid battery

Nickel-cadmium battery

What is the primary function of the electrolyte in an electric cell?

To generate electrons

To conduct electricity outside the cell

To separate the anode and cathode (correct)

To store chemical energy

Which of the following components is positively charged in an electric cell?

Cathode Signup and view all the answers

What is a key characteristic that defines the lifespan of a rechargeable electric cell?

The number of charge/discharge cycles Signup and view all the answers

What unit is used to measure electrical power consumption?

Watt (W) Signup and view all the answers

How is monthly electricity cost calculated?

kWh x unit price Signup and view all the answers

If a stove has a power rating of 3000 watts and is used 2 hours a day for 25 days, how many kilowatt-hours does it consume in a month?

150 kWh Signup and view all the answers

Which device has the highest power consumption according to the provided data?

Geiser Signup and view all the answers

What is the total kilowatt-hours the microwave uses in a month if it operates for 1 hour a day over 20 days?

10 kWh Signup and view all the answers

What are fossil fuels primarily formed from?

Plants and animals from millions of years ago Signup and view all the answers

What is the function of a generator in a power plant?

To convert mechanical energy into electrical energy Signup and view all the answers

Which of the following is a disadvantage of coal power stations?

Production of sulfur rain Signup and view all the answers

What role does uranium play in nuclear power generation?

It serves as a fuel for nuclear reactions Signup and view all the answers

What is the purpose of transmission in the national electricity network?

To transport electricity over long distances Signup and view all the answers

Which of the following best describes renewable electricity generation methods?

Utilize natural sources that replenish naturally Signup and view all the answers

What is a primary disadvantage of nuclear power?

It can lead to the generation of radioactive waste Signup and view all the answers

What does the distribution process in the national electricity network involve?

Utilizing low-voltage lines and substations Signup and view all the answers

What happens to electrical energy when it flows through a conductor?

Some energy is lost as heat due to resistance. Signup and view all the answers

Which of the following factors does NOT affect the resistance of a resistor?

Color of the resistor. Signup and view all the answers

In a series circuit, how does the total voltage relate to the voltage across individual resistors?

It is the sum of the voltages across the individual resistors. Signup and view all the answers

When resistors are connected in parallel, how does the total current relate to the current through individual resistors?

It is the sum of the currents through each of the resistors. Signup and view all the answers

Which statement is true regarding the behavior of current in a series circuit?

Current remains constant throughout the circuit. Signup and view all the answers

What is the effect of increasing the length of a wire on its resistance?

Resistance increases. Signup and view all the answers

Which characteristic defines a battery made up of multiple cells connected in series?

It provides a total voltage equal to the sum of the individual cell voltages. Signup and view all the answers

How does temperature affect the resistance of a metallic conductor?

Higher temperatures increase resistance. Signup and view all the answers

Study Notes

Elektriese Selle

Definisie: Elektriese selle, of battery cells, is devices that convert chemical energy into electrical energy through electrochemical reactions.
Basiese Komponente:
- Anode: Negatief gekonterde elektrode waar oksidasie plaasvind.
- Katode: Positief gekonterde elektrode waar reduksie plaasvind.
- Elektroliet: Geleier van ioniese bewegings wat die anode en katode skei.
Werkingsbeginsel:
- Chemiese reaksies tussen die anode, katode en elektroliet genereer elektrone.
- Elektrone vloei van die anode na die katode deur 'n externe stroombaan, wat 'n elektrisiteitsstroom veroorsaak.
Tipes Elektriese Selle:
- Primêre Selle: Eenmalig gebruik, nie herlaaibaar (bv. Alkaliese batterye).
- Sekondêre Selle: Herlaaibaar (bv. Li-ion, loodzuur batterye).
Toepassings:
- Voeding van elektroniese toestelle (bv. afstandbeheer, mobiltelefone).
- Aangedrewe voertuie (bv. elektriese motors).
- Energiebergingsoplossings (bv. sonkragstelsels).
Belangrike Kenmerke:
- Spanning (Volt): Energiemaat van die sel.
- Kapaciteit (Ah): Hoeveelheid energie wat 'n sel kan stoor en lewer.
- Levensiklus: Aantal herlaai / ontladings voordat die sel sy doeltreffendheid verloor.
Gevolge van ou batterye:
- Moet korrek weggegooi word om omgewingsbesoedeling te voorkom.
- Herwinning van materiale soos lood, nikkel, en lithium is belangrik.
Navorsing en Ontwikkeling:
- Verbetering in batterye se energiedigtheid en laaityd.
- Ontwikkeling van volhoubare en hernubare energiebronne saam met elektriese selle.

Electric Cells

Definition: Electric cells, or battery cells, convert chemical energy into electrical energy via electrochemical reactions.
Components:
- Anode: Negatively charged electrode where oxidation occurs.
- Cathode: Positively charged electrode where reduction occurs.
- Electrolyte: Conducts ionic movement, separating anode and cathode.
Working principle:
- Chemical reactions between anode, cathode, and electrolyte generate electrons.
- Electrons travel from anode to cathode through an external circuit, creating an electric current.
Types of Cells:
- Primary Cells: Single use, non-rechargeable (e.g. alkaline batteries).
- Secondary Cells: Rechargeable (e.g. lithium-ion, lead-acid batteries).
Applications:
- Powering electronics (e.g. remote controls, mobile phones).
- Electric vehicles (e.g. electric motors).
- Energy storage solutions (e.g. solar power systems).
Key Features:
- Voltage (Volt): Measures the cell's energy output.
- Capacity (Ah): Amount of energy a cell can store and deliver.
- Cycle Life: Number of charge/discharge cycles before the cell loses efficiency.
Consequences of Old Batteries:
- Dispose correctly to prevent environmental pollution.
- Recycling materials like lead, nickel, and lithium is crucial.
Research and Development:
- Improving battery energy density and charging time.
- Developing sustainable and renewable energy sources alongside electric cells.

Electrical Cells and Circuits

An electrical cell is a system where chemical reactions cause the flow of electricity through an external circuit.
Cells are sources of electricity.
A battery is a collection of cells connected together.

Resistance

Conductors heat up when electrical current flows through them, some energy is lost as heat.
All conductors have resistance.
A resistor is a conductive material used to control the flow of electricity or provide useful energy transfer, examples include light bulbs, rheostats, motors, and light-emitting diodes.

Factors Affecting Resistance

Type of material: different conductive materials have different resistance to electrical current
Thickness of the conductor: thinner wires have more resistance than thicker wires
Length of the conductor: longer wires have more resistance than shorter wires
Temperature of the conductor: warmer conductors (metals) have higher resistance than colder conductors.

Series Circuits

When cells are connected in series, the total voltage is the sum of the voltages of individual cells.
Resistors can be connected in series in a circuit.
The total voltage across the battery is the same as the sum of the voltages across each resistor.
- A resistor with higher resistance will have a higher voltage across it.
- A resistor with lower resistance will have a lower voltage across it.
Current is the same when measured at any point in a given series circuit.
The total current in the circuit decreases with the addition of each resistor in series.

Parallel Circuits

When cells (with the same voltage) are connected in parallel, the voltage across them all is the same as for one cell.
Resistors can be connected in parallel in a circuit.
The voltage across each resistor connected in parallel is the same.
The total current through the battery is the same as the sum of the currents through the resistors.
The total current in the circuit increases with each resistor added in parallel.
The lighting system in our homes is usually connected in parallel.
Illegal connections to the Eskom network supply can be dangerous and are considered energy theft.

Energy and the National Electricity Network

Electricity generation:
- Non-renewable electricity generation methods: use fossil fuels like coal, natural gas, oil, and nuclear power
  - Fossil fuels are formed from plants and animals buried deep underground millions of years ago.
- Renewable electricity generation methods: use renewable sources such as solar energy, wind energy, hydropower, geothermal energy, and biomass to generate electricity.

How Coal Power Stations Work

Electricity is the flow of electrons.
Most power plants heat water to form steam which turns turbines, which in turn rotate a generator.
A generator is a machine that produces an electric current by rotating a coil of wire within a magnetic field.
The electricity is then channeled to the national electricity network.
Disadvantages of coal power stations include the formation of acid rain and contributing to global warming.

Nuclear Power in South Africa

Uses nuclear reactions (nuclear fission and nuclear fusion) to generate usable heat and electricity.
Serves as an alternative energy source and provides 5% of South Africa's energy needs.
The element Uranium is used as fuel and is mined from rock minerals.
Koeberg Nuclear Power Station (Cape Town) is the only commercial nuclear power station in South Africa.
Advantages: Uses a sustainable energy source.
Disadvantages: Produces radioactive waste.

Coal vs Nuclear Power Stations

The same process is followed, only the fuel source differs.

National Electricity Network

A network of cables, masts (pylons), and transformers to distribute electricity across the country.
Steps to provide electricity to consumers:
- Generation: using an energy source to generate electricity.
- Transmission: using high-voltage lines to distribute electricity from power plants to remote areas.
- Distribution: using low-voltage lines, substations, and transformers to supply electricity to local consumers.

Cost of Electrical Power

Electrical power is the rate of electrical energy supply, measured in watts (W) or kilowatts (kW), e.g., 800 W or 2000 W.
Our energy consumption is calculated in kilowatt-hours (kWh).
Formulas:
- kWh = power of the device (kW) x number of hours used (h).
- Cost = kWh x unit price of electricity
  - e.g., Cost = 2 kW x 150 hours x 79.5 c = 23 850 c or R238.50

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Description

Explore the fundamental principles of electric cells, also known as battery cells. Understand their basic components including anodes, cathodes, and electrolytes, and discover the differences between primary and secondary cells. Learn about their various applications in everyday technology.