Question

help me to solve this question ​

Answer 1

Answer:

(a)R=5.9447Ω

Explanation:

Given specific resistance(ρ) of copper is 1.68 x 10⁻⁸ Ωm.

Its length(l) is 100 m.

Radius(r) of the wire is 0.3 mm or 0.3 x 10⁻¹ cm or 0.3 x 10⁻³ m.

Therefore area of cross section(A) is π(0.3 x 10⁻³)².       ( area = πr²)

We know that resistance of a wire is

R = ρl/A

∴R = 1.68 x 10⁻⁸ x 100 /π(0.3 x 10⁻³)²

⇒R = 1.68 x 10⁻⁶/π x 9 x 10⁻⁸

⇒R =1.68/9π x 10²

π≈3.14

⇒R=0.1866/3.14 x 10²

⇒R=0.059447 x 10²

⇒R=5.9447Ω