Question

The resistance of a wire of length 300 m and cross-section area 1.0 mm² made of material of resistivity 1.0 × 10⁻⁷ Ωm is ______.

विकल्प

• 2 Ω

• 3 Ω

• 20 Ω

• 30 Ω

Answer 1

The resistance of a wire of length 300 m and cross-section area 1.0 mm² made of material of resistivity 1.0 × 10⁻⁷ Ωm is 30 Ω.

Explanation:

Given: Length (l) = 300 m

Cross-sectional area (A) = 1.0 mm² = 1.0 × 10⁻⁶ m²

Resistivity (ρ) = 1.0 × 10⁻⁷ Ωm

We know that,

Resistance (R) = `(1.0 xx 10^-7) xx 300/(1.0 xx 10^-6)`

R = 1.0 × 10⁻⁷ × 300 × 10⁶

R = 300 × 10⁻¹

R = 30 Ω