A metal wire has diameter of 0.25 mm and electrical resistivity of 0.8 ×10-8 Ω-m. The length of this wire required to make a resistance of 5 is [[1]] m.

A metal wire has diameter of

0.25 mm

and electrical resistivity of

0.8 \times 10^{- 8} Ω - m

. The length of this wire required to make a resistance of

5

30.62 m

.
Given, diameter of wire = 0.25 mm
Resistivity, ρ = 0.8 x10-8 Ω-m
Resistance, R =

5

We know that,

R = l / A

⇒

l = AR /

ρ
⇒

l = \frac{π \times [\frac{0.25}{2} \times 10^{- 3}] \times 5}{0.8 \times 10^{- 8}}

⇨

\frac{π \times 5 \times 1.56 \times 10^{- 8}}{0.8 \times 10^{- 8}}

= 30.62 m

A metal wire has diameter of $0.25 mm$ and electrical resistivity of $0.8 \times 10^{- 8} Ω - m$ . The length of this wire required to make a resistance of $5$ is [[1]] m.