Question

12. Calculate the resistance of 2 m long copper wire of radius 2 mm. (Resistivity of
copper = 1.72 x 10^-ohm m).

Answer 1

Answer:

R = (ro × l)/A

Explanation:

hope the answer will help you

Answer 2

Answer:

Given :

• 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

Solution :

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

We know that, Area = πr²

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

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

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

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

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