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    ​The filament of a bulb is made extremely thin and long in order to achieve:​
    Question

    ​The filament of a bulb is made extremely thin and long in order to achieve:​

    A.

    ​high resistance​

    B.

    ​high current​

    C.

    ​high resistivity​

    D.

    ​high voltage​

    Correct option is A

    The correct answer is option (a) high resistance

    The filament of a bulb is made extremely thin and long in order to achieve high resistance.

    ​High resistance: When the filament is thin and long, it increases the length through which the current flows, thus increasing the resistance. The resistance RRR of a conductor is given by the formula:

    R=ρLA\frac{L}{A}

    where:

    ​​R is resistance, L is the length of the filament, A is the cross-sectional area of the filament


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