Electricity Basics Quiz
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Questions and Answers

What type of current is typically supplied to our homes?

  • Static Current
  • Alternating Current (A.C.) (correct)
  • Residual Current
  • Direct Current (D.C.)

Electrical energy is only measured in joules (J).

False (B)

What is the primary purpose of the earth (ground) wire?

To provide safety by preventing electric shocks.

One kilowatt-hour represents the energy consumption of a device with a power rating of _____ when it operates for one hour.

<p>one kilowatt</p> Signup and view all the answers

Which of the following is NOT a source of electricity?

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

Match the wire types with their functions:

<p>Live Wire = Carries current to the appliance Neutral Wire = Completes the circuit Earth Wire = Prevents electric shocks</p> Signup and view all the answers

The commercial unit of electrical energy is referred to as the megawatt-hour (MWh).

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

What happens to the magnitude and polarity of alternating current (A.C.) over time?

<p>It changes with time.</p> Signup and view all the answers

Which device is used to measure the amount of electrical energy consumed?

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

A parallel circuit allows devices to operate independently of each other.

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

What is the formula to calculate energy consumed in kilowatt-hours?

<p>Energy (kWh) = Power (kW) × Time (h)</p> Signup and view all the answers

A safety device that protects against excessive current flow is called a _____.

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

Match the following electrical devices with their functions:

<p>Electric Meter = Measures electricity consumption Fuse = Protects against excessive current Miniature Circuit Breaker = Automatically switches off during overload Series Circuit = Components connected one after another</p> Signup and view all the answers

What characteristic is true about an electric fuse?

<p>Short wire with a low melting point (A)</p> Signup and view all the answers

Poor insulation of wires is a contributing factor to electric shock.

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

Name one precaution that should be taken to ensure electrical safety.

<p>Do not touch switches with wet hands.</p> Signup and view all the answers

Which statement is true regarding static electricity?

<p>It occurs due to an imbalance of electric charges. (D)</p> Signup and view all the answers

Like charges attract each other.

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

What are the two types of electric charges?

<p>Positive charges and negative charges</p> Signup and view all the answers

Insulators restrict the movement of electric charge due to very few free ______.

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

Match the following methods of charging with their descriptions:

<p>Conduction = Contact with a charged object Induction = No direct contact required Charging by rubbing = Imbalance of charge due to friction Electroscope = Detects electric charge presence</p> Signup and view all the answers

Which of the following is NOT a common insulator?

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

An electroscope is used to detect the magnitude of electric current.

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

Explain how a conductor is charged by conduction.

<p>A charged object is brought into contact with a neutral conductor, transferring excess charge to the conductor.</p> Signup and view all the answers

What is the main function of a lightning conductor?

<p>To provide a path for electrical charge to safely travel to the ground (D)</p> Signup and view all the answers

Gold leaves in an electroscope will repel each other when they have opposite charges.

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

What should you do if you are caught outside during a thunderstorm?

<p>Rush to a safe place, such as a low house or building, and stay inside.</p> Signup and view all the answers

When lightning strikes a building, it can cause fires, __________, or electrical failures.

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

Match the following safety measures with their descriptions:

<p>Do not stand under a tree = To avoid falling branches during a storm Sit inside a car = To provide protection from lightning Take out plugs = To prevent damage to electronics Do not use wired phone = To avoid electric shock risk during a storm</p> Signup and view all the answers

Flashcards

Electrical Energy

The electrical energy carried by the current from the power source to an appliance.

Electrical Power

The rate at which electrical energy is consumed by a device, calculated by multiplying voltage, current, and time.

Direct Current (DC)

The type of electrical current where the direction and magnitude of flow remain constant.

Alternating Current (AC)

The type of electrical current where the flow changes direction periodically, alternating between positive and negative.

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Live Wire

The wire that carries the electrical current from the power source to the appliance. It's typically red or brown in color.

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Neutral Wire

The wire that completes the circuit by returning current back to the power source. It's usually black or blue.

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Earth Wire

The wire that provides a path for electricity to flow directly to the ground in case of a fault, preventing electrical shocks. It's typically green or yellow-green.

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Kilowatt-hour (kWh)

The unit used to measure electrical energy commercially. It represents the amount of energy consumed by a 1 kilowatt device in one hour.

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Energy Consumption

The amount of electrical energy used, measured in kilowatt-hours (kWh).

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Electric Meter

A device that measures the amount of electrical energy used by a household or business.

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Electric Fuse

A safety device that protects electrical circuits from excessive current flow, which can cause overheating or damage.

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Miniature Circuit Breaker (MCB)

An automatic switch that protects electrical circuits from overloads and short circuits.

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Series Circuit

A type of electrical circuit where components are connected one after the other, so if one breaks, the entire circuit stops working.

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Parallel Circuit

A type of electrical circuit where components are connected alongside each other, so if one breaks, the others continue working.

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Short Circuit

A dangerous situation that can occur in electrical circuits due to excessive current flow, often caused by overloading or faulty wiring.

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Electric Shock

An electrical hazard that can occur when a person comes into contact with a live wire, which can cause serious injury or death.

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What is an electroscope?

A device that visually indicates the presence and magnitude of electric charge. It works by inducing a charge in gold leaves, causing them to spread apart due to repulsion.

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What is Lightning?

Lightning is a powerful electrical discharge during thunderstorms, creating a bright flash of light and a loud sound called thunder.

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What is a Lightning Conductor?

Lightning conductors direct electrical charge safely to the ground when lightning strikes a building, preventing damage.

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How does an electroscope work?

When a charged object is brought near an electroscope, the gold leaves will spread apart. If the object is positively charged, it will attract electrons from the leaves, making them positive. If the object is negatively charged, it will repel electrons, making the leaves negative.

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What safety measures should you take during a lightning storm?

To stay safe during a lightning storm, avoid tall objects like trees or buildings, seek immediate shelter in a closed car or building, and avoid using phones or electrical appliances.

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Static Electricity

The accumulation of electric charge on the surface of objects, caused by an imbalance of charges due to conduction or induction.

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Conductors

Materials that allow electric current to flow through them easily due to the presence of free electrons.

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Insulators

Materials that resist the flow of electric current due to having very few free electrons.

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Charging by Conduction

A method of charging a conductor by bringing a charged object into contact with it, transferring the excess charge.

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Charging by Induction

A method of charging a conductor without direct contact, using an electric field to induce a charge separation.

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Electroscope

A device used to detect the presence and magnitude of electric charge on an object.

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Gold Leaf Electroscope

A type of electroscope using gold leaf to detect and measure electric charge.

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Like Charges Repel, Unlike Charges Attract

Objects with the same charges repel each other, while objects with opposite charges attract each other.

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Study Notes

Electricity

  • Household electricity powers various home appliances like lighting, heating, cooling, and cooking. It's delivered as alternating current (AC) through a distribution network.

Types of Current

  • Direct Current (DC): Current remains constant over time. Examples include cells and batteries.
  • Alternating Current (AC): Current changes in magnitude and polarity over time. Examples include mains electricity and electric generators.

Sources of Electricity

  • The electric cell/battery
  • The mains (electricity from local electricity board)
  • Generators (or dynamos)
  • Solar cells

Electrical Energy and Power

  • Electrical energy is transferred by electric current from a power source to a device.
  • Energy consumption depends on voltage, current, and time. It's measured in joules (J) or kilowatt-hours (kWh).

Colour Coding of Wires

  • Live (or Phase) Wire: Carries current from the power source to the appliance (typically red or brown).
  • Neutral Wire: Completes the circuit, carrying current back to the power source (usually black or blue).
  • Earth (or Ground) Wire: Provides safety by connecting the appliance to the ground, preventing electric shocks (green or yellow-green striped).

Commercial Unit of Electrical Energy

  • The kilowatt-hour (kWh) is the commercial unit used to measure energy for billing.

Electric Meter

  • An electric meter measures the electrical energy used by a household or business.
  • Analog and digital meters are the two main types.

Electric Fuse (Safety Device)

  • A fuse is a safety device to prevent excessive current flow, which can overheat and cause fires.
  • It's a thin wire with a low melting point connected in series in an electrical circuit.
  • Fuse wire thickness depends on its current rating.

Miniature Circuit Breaker (MCB)

  • An MCB is an automatic electrical switch to protect electrical circuits from overloads and short circuits.

Household Electrical Circuits

  • These are networks of wires, switches, outlets, and appliances delivering electricity.
  • Series Circuits: Components connected one after another; if one fails, the entire circuit stops.
  • Parallel Circuits: Components are alongside each other; if one fails, other components operate independently.

Hazards of Electricity

  • House circuits overloaded may cause short circuits.
  • Poor insulation may cause short circuits or excess current flow.
  • Electric shock occurs when touching live wires.

Precautions

  • Do not touch switches with wet hands.
  • Ensure connections to plugs, sockets, and switches are securely joined.
  • Appliances should be earthed correctly.
  • Do not repair appliances while in use.

Static Electricity

  • Static electricity is the buildup of electric charge on objects.
  • It's different from current electricity, which involves the flow of charge.
  • Objects can be charged by rubbing.
  • Like charges repel, unlike charges attract.

Conservation of Charge

  • Before rubbing, both objects are uncharged.
  • On rubbing, both objects get equal and opposite charges.

Conductors and Insulators

  • Conductors: Materials that allow electric current to flow easily (e.g., metals).
  • Insulators: Materials that do not allow electric current to flow easily (e.g., rubber, glass, wood).

Methods of Charging a Conductor

  • Charging a conductor involves creating an imbalance of electric charge, either by conduction or induction.

Charging by Conduction

  • A charged object contacts a neutral conductor making the conductor charged.

Charging by Induction

  • Transferring electrical energy/charge without direct contact.

Electroscope

  • An electroscope is a device used to detect and measure electric charge, particularly to determine the charge's polarity.
  • Gold leaf electroscopes provide a visible indication of the charge's presence and magnitude.

Lightning

  • Lightning is a sudden electrostatic discharge during thunderstorms.
  • Safety measures include avoiding standing under trees or tall buildings, sitting inside a car, and avoiding carrying umbrellas or using wired phones during storms.
  • A lightning conductor is a device used to protect buildings from being damaged. It provides a direct path for electrical charges to travel safely to the ground.

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Description

Test your knowledge on the fundamentals of electricity, including types of current, sources, and electrical energy. This quiz covers key concepts like AC and DC, as well as the importance of wire color coding. Perfect for anyone looking to understand household electricity and its applications.

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