When a voltage difference is applied to a piece of metal wire, a 8-mA current flows through it. If this metal wire is now replaced with a si

Question

When a voltage difference is applied to a piece of metal wire, a 8-mA current flows through it. If this metal wire is now replaced with a silver wire having twice the diameter of the original wire, how much current will flow through the silver wire

in progress 0
Tryphena 5 years 2021-08-29T03:18:45+00:00 1 Answers 37 views 0

Answers ( )

  1. nguyetanh
    0
    2021-08-29T03:20:10+00:00
    Reply

    Answer:

    Explanation:

    The resistance of a wire can be given by the following expression

    R=\frac{\rho\times L}{A }

    where R is resistance , ρ is specific resistance , L is length of wire and A is cross sectional area

    specific resistance of metals are almost the same . So in the present case ρ and l are same . Hence the formula becomes

    R = k / A where k is a constant .

    The diameter of wire becomes two times hence area of cross section becomes 4 times or 4A .

    Resistance becomes 1/4 times . Hence if resistance of metal wire is R , resistance of silver wire will be R / 4 .

    current = voltage / resistance

    In case of metal wire

    8 x 10⁻³ = V / R

    In case of silver wire

    I = V / (R / 4 ) , I is current , V is potential difference .

    I = 4 x V/R

    = 4 x 8 x 10⁻³ A

    = 32 mA.

Leave an answer

Browse

Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )