Question

Calculate the resistance of 2 m long copper wire of radius 2 mm. (Resistivity of
copper = 1.72 x 10^-8ohmm)
please ans fast​

Answer 1

here, length of the wire=1km=100m

$radius \: of \: the \: wie = 1mm = {10}^{ - 3m}$

$resetivity \: of \: copper = 1.72 \times {10}^{ - 8}$

cross-secrional area of the wire,

A=πr^2= 3.14×(10^-3m^2)=3.14×10.6m^2

if uh still didn't understand then see the attachment

Answer 2

Provided :

• Length of the wire = 2 km

Converting km in m

As we know that, 1 km = 1000 m

• Therefore, Length of the wire = 2000 m

• Radius of copper wire = 2 mm

As we know that, 1 mm = 10-³ m

• Therefore, Radius of copper wire = 2 × 10-³ m

Answer:

$:\implies \sf Resisiatnce = \dfrac{Resistivity \times Length}{Area}$

We know that, Area = πr²

$:\implies \sf Resisiatnce = \dfrac{Resistivity \times Length}{\pi {r}^{2} }$

$:\implies \sf Resisiatnce = \dfrac{1.72 \times {10}^{ - 8} \times 2000}{ \dfrac{22}{7} \times \left( 2 \times {10}^{ - 3} \right)^{2} }$

$:\implies \sf Resisiatnce = \dfrac{0.0000344}{ \dfrac{22}{7} \times 0.000004 }$

$:\implies \sf Resisiatnce = \dfrac{0.0000344}{ 0.00001256 }$

$:\implies \textsf{ \textbf{ Resisiatnce = 2.73 \Omega }}$