Question

What will be the resistivity of a metal wire of 2 m
length and 0.6 mm in diameter, if the resistance of
the wire is 50 n.​

Answer 1

Answer:

Explanation: Resistance of a material depends upon length and area of cross section of the wire as 1) R is directly proportional to length and 2) R is inversely proportional to area of cross section

R α l/A => R = resistivity (l/A)

Here: length, l = 2m; Diameter = 0.6mm => radius = 0.3mm = 0.3 * 0.001m = 0.00003m; Resistance = 50 ohm; Resistivity = ?

Resistivity = RA/l = 50 * (πr squared)/2 = 50*3.14*0.0000000009/2 = 7.1 * 10 raised to the power -8 ohm-meter

Answer 2

Answer:

Resistivity of the wire is 706.5 × 〖10〗^(-8)Ω m.

Explanation:

Resistance (R) = 50 Ω

Length of the wire ( l ) = 2 m

Diameter of the wire = 0.6 mm

Radius = 0.6/2  = 0.3 mm= 3 × 〖10〗^(-4)m

Resistivity (ρ) = ?

Area of cross sectional area of wire (A) = πr^2

= 3.14 ×〖( 3 × 〖10〗^(-4))〗^2  

=3.14×9×〖10〗^(-8)

= 28.26 × 〖10〗^(-8)m

We know,

ρ = RA/l

ρ = 〖50 × 28.26 ×10〗^(-8)/2

ρ = 25 × 28.26 × 〖10〗^(-8)

ρ = 706.5 × 〖10〗^(-8)