Question

If negligibly small current is passed though a wire of length 15 m & resistance of 5Ω, having uniform cross section of 6 × 10⁻⁷ m², then coefficient of resistivity of material is(a) 1 × 10⁻⁷ Ω–m(b) 2 × 10⁻⁷ Ω–m(c) 3 × 10⁻⁷ Ω–m(d) 4 × 10⁻⁷ Ω–m

Answer 1

option B should be the answer

Answer 2

Answer:

B) 2.0×10−7Ωm

Explanation:

Length of the wire, l = 15cm  (Given)

Resistance ( R) = 5.0Ω  (Given)

Area of cross-section of the wire A = 6.0 × 10- 7m² (Given)

Resistivity of the material of the wire = ÃÂ

ρ=?

Resistance is also related with the resistivity as -

R = ρl/A

ρ = RA/l

=5.0×6×10−7/15

=2.0×10−7

Thus, the coefficient of resistivity of the material is 2.0×10−7Ωm