A copper wire and an iron wire of equal length l and diameter d are joined, and a potential difference V is applied between the ends of the composite wire. Calculate the potential difference (in volts) across the iron wire. Assume that l = 2.97 m, d = 0.88 mm, and V = 157 V.

Respuesta :

Answer:

The potential difference across iron wire is 133.95 V

Solution:

As per the question:

Length, l = 2.97 m

Diameter. d = 0.88 mm = [tex]0.88\times 10^{- 3}\ m[/tex]

Voltage, V = 157 V

Now,

We know that the resistivity of iron, [tex]\rho_{I} = 10\ S[/tex]

Resistivity of copper, [tex]\rho_{I} = 1.72\ S[/tex]

Now,

The potential difference across the iron wire:

V' = [tex]\frac{\rho_{I}V}{\rho_{I} + \rho_{C}}[/tex]

V' = [tex]\frac{10\times 157}{10 + 1.72} = 133.95\ V[/tex]

Answer:

The potential difference across the iron wire 134.2 V.

Explanation:

Given that,

Length = 2.97 m

Diameter = 0.88 mm

Total potential = 157 V

We know that,

The resistivity of iron wire

[tex]\rho_{i}=10\times10^{-8}\Omega m[/tex]

The resistivity of copper wire

[tex]\rho_{c}=1.7\times10^{-8}\Omega m[/tex]

The voltage for each wire is proportional to the resistivity.

We need to calculate the resistance for copper wire

Using formula of resistance

[tex]R_{c}=\dfrac{\rho\times l}{A}[/tex]

Put the value into the formula

[tex]R_{c}=\dfrac{1.7\times10^{-8}\times2.97}{\pi\times(0.44\times10^{-3})^2}[/tex]

[tex]R_{c}=0.0830\ \Omega[/tex]

We need to calculate the resistance for iron wire

Using formula of resistance

[tex]R_{i}=\dfrac{\rho\times l}{A}[/tex]

Put the value into the formula

[tex]R_{i}=\dfrac{10\times10^{-8}\times2.97}{\pi\times(0.44\times10^{-3})^2}[/tex]

[tex]R_{i}=0.4883\ \Omega[/tex]

The total resistance is

[tex]R =R_{c}+R_{i}[/tex]

[tex]R=0.0830+0.4883[/tex]

[tex]R=0.5713\ \Omega[/tex]

We need to calculate the potential difference across the iron wire

Using formula of potential difference

[tex]V_{i}=\dfrac{VR_{i}}{R}[/tex]

Put the value into the formula

[tex]V_{i}=\dfrac{157\times0.4883}{0.5713}[/tex]

[tex]V_{i}=134.2\ V[/tex]

Hence, The potential difference across the iron wire 134.2 V.