Question

The resistivity of a metal wire is 10 x 10 −8 Ω m at 20°C. Find the resistance of the same wire of 2 meter length and 0.3 mm thickness.

Answer 1

Given, Resistivity (ρ) = 10 x 10−8 Ω m, Length ( l ) = 2 m, Diameter = 0.3 mm

Resistance (R) =?

Now, Radius of wire = Diameter / 2 = 0.3 mm / 2 = 0.15 mm = 1.5 x 10−5 m

Now, area of cross section of wire = π r2

Or, A = 3.14 x (1.5 x 10−5)2

Or, A = 70.65 x 10−10 m2


we know that

R = ρ l/A

then you got the value of R = ?

Answer 2

Answer:

Given, Resistivity (ρ) = 10 x 10−8 Ω m, Length ( l ) = 2 m, Diameter = 0.3 mm

Resistance (R) =?

Now, Radius of wire = Diameter / 2 = 0.3 mm / 2 = 0.15 mm = 1.5 x 10−5 m

Now, area of cross section of wire = π r2

Or, A = 3.14 x (1.5 x 10−5)2

Or, A = 70.65 x 10−10 m2

we know that

R = ρ l/A

then you got the value of R = ?

Explanation: