Question

Find the length of nichrome wire of resistivity 100×10-6 ohm -m of area of cross section 1mm square to yield a resistance of 10 ohm​

Answer 1

Given:

Resistivity of Nichrome wire, ρ = 100 × 10⁻⁶ Ωm

Area of cross section, A = 1 mm² = 10⁻⁶ m²

Resistance, R = 10 Ω

To Find:

Length of nichrome wire, i.e., l

Calculation:

- We know that Resistance is given by the formula :

R = ρ × l / A

⇒ l = R × A / ρ

⇒ l = 10 × 10⁻⁶ / (100 × 10⁻⁶)

⇒ l = 10 / 100

⇒ l = 0.10 m = 100 mm

- SO the length of nichrome wire is 100 mm ( or 10 cm)