Question

An iron wire of length 4cm having a resistance of 40 ohms ans specific resistivity of iron is 5×10 power -3 ohms/m. Then the area of cross section of the iron wire is
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Answer 1

Answer:

A= 5× 10 raised to power -4 meter.square

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Answer 2

Answer:

  =>The area of a cross-section of the iron wire is 5x$10^{-6}$ $m^{2}$ .

Step by Step Explanation:

We will glance at the concepts of resistance, resistivity, and how to calculate the minimum cross-sectional area of any desired conductor.

given data:

• length(L)=4cm = 4x$10^{-2}$m,      (conductor length should be in meters, so the given cm value is converted into m)                                                                      

• resistance(R)=40Ω,

• resistivity(ρ)=5x$10^{-3}$Ω/m.

the general equation to find the conductor resistance is given below,

 Resistance = Resistivity x(Length / Area )

R = ρx(L/A),

• R is the Resistance of material, in Ohms(Ω),

        The opposition to current flow is referred to as electrical resistance.

• ρ is the Material Resistivity, in Ω/m,                                                                               The resistance of a conducting material per unit length with a unit area of the cross-section is defined as resistivity.
• L is the Conductor Length, in m,                                                               It is the length of the conductor.
• A is the Cross-sectional Area, in $m^{2}$.

by using the above equation, we will find the area of a cross-section of the iron wire,

A = ρx(L/R)

by substituting the given data,

A = 5x$10^{-3}$x(4x$10^{-2}$/40)

  = $\frac{1}{2}$x$10^{-5}$

  = 0.5x$10^{-5}$

  = 5x$10^{-1}$x$10^{-5}$

A = 5x$10^{-6}$ $m^{2}$ .

∴ 5x$10^{-6}$ $m^{2}$ is the area of a cross-section of the iron wire.