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

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

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

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

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

    <p>True</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.</p> Signup and view all the answers

    Like charges attract each other.

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

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

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

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

    <p>False</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

    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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    Class 8 ICSE Physics Electricity Notes PDF

    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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