Electricity

•    Electricity plays a very important role in our daily life. We use electricity to light our houses, schools, offices etc.
•    Electric cell is a common source of electricity.
•    A group of two or more cells is known as battery.
•    Some other sources of electricity are generators and solar cells.
•    The path along which electricity flows is known as a circuit.
•    The substance that allows electricity to flow through it is known as conductor. Examples: metals, human body and impure water, etc.
•    The substance that does not allow electricity to flow through it is known as insulator. Examples: Rubber, plastic, cotton, etc.


•    An electric circuit is incomplete if there is an insulator in its path.
•    Every part of electric circuit must be made of conductors.
•    Switch is a device used to open or close an electric circuit.
•    An electrical appliance will only work if the electric circuit is made up of conductors only and its path is closed.
•    In series all appliances work together and if one appliance does not work, others will also not work.
•    In parallel circuit all appliances work independently.
•    Current flows, due to flow of charges.
•    In metals, the flow of current is due to motion of electrons but in liquids the flow of electrons is due to ions.
•    The rate of flow of charges per unit time is known as electric current.
•    S.I unit of current is ampere (A).
•    Before the switch of a circuit is on, it should be checked that all the components of the circuit are properly connected. The connection wire is nowhere naked, but is insulated everywhere. The switches must not be touched with wet hands.

 

 

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  • Q1

    Label the anode, cathode and electrolyte in the given diagram of a dry cell. Also state the name of the substances for each of them.

    Marks:2
    Answer:

    Label the anode, cathode and electrolyte in the given diagram of a dry cell. Also state the name of the substances for each of them.

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  • Q2

    How is a battery made?

    Marks:1
    Answer:

    A battery is made by combining two or more cells in series.

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  • Q3

    Name the electrolyte generally used in a dry cell.

    Marks:1
    Answer:

    Ammonium chloride paste is generally used as electrolyte in a dry cell.

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  • Q4

    Name any two main sources of electricity.

    Marks:1
    Answer:

    The two main sources of electricity are

    (a) the electric cell

    (b) the generator

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  • Q5

    Define electric current.

    Marks:1
    Answer:

    Electric current is defined as the flow of electrons per unit time.

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