Question

A rear window defroster consists of a long, flat wire bonded to the inside surface of the window. When current passes through the wire, it heats up and melts ice and snow on the window. For one window the wire has a total length of 12.2 m, a width of 1.6 mm, and a thickness of 0.11 mm. The wire is connected to the car's 12.0 V battery and draws 7.5 A. What is the resistivity of the wire material?

Answer 1

Answer:

The resistivity of the wire material is $2.30\times10^{-8}\ \Omega-m$

Explanation:

Given that,

Length = 12.2 m

Width = 1.6 mm

Thickness = 0.11 mm

Voltage = 12.0

Current = 7.5 A

We need to calculate the resistivity of the wire material

Using formula of resistivity

$\rho=\dfrac{RA}{l}$....(I)

Using ohm's law

$R =\dfrac{V}{I}$

Put the value of R in equation (I)

$\rho=\dfrac{VA}{lI}$

Put the value into the formula

$\rho=\dfrac{12.0\times1.6\times10^{-3}\times0.11\times10^{-3}}{7.5\times12.2}$

$\rho=2.30\times10^{-8}\ \Omega-m$

Hence, The resistivity of the wire material is $2.30\times10^{-8}\ \Omega-m$