Apr 20, 2017

0.2377 $\Omega$

#### Explanation:

To find the resistance of a copper wire with given parameters we use
$R = \frac{\rho \cdot l}{A}$
$\frac{1.68 \cdot {10}^{- 8} \cdot 25}{3.14 \cdot 5.627 \cdot {10}^{- 7}} = 0.2377 \Omega$

we got diameter=1.5mm which is equal to $0.0015 m$
but in scientific notion we write it $1.5 \cdot {10}^{- 3} m$
Dividing it by 2 we get ..
$0.75 \cdot {10}^{- 3} m = 7.5 \cdot {10}^{- 4} m$