Consider a copper wire of length 1m and area of cross-section 1mm². Given the resistivity of the copper is 1.7 × 10⁻⁶ Ω cm. What is the resistance of this wire?
17 milli-ohm
1.7 milli-ohm
0.17 milli-ohm
0.17 ohm
Answer is Right!
Answer is Wrong!
This question was previously asked in
UPSC Geoscientist – 2021
Given:
ρ = 1.7 × 10⁻⁶ Ω cm
L = 1 m = 100 cm
A = 1 mm² = (0.1 cm)² = 0.01 cm²
R = (1.7 × 10⁻⁶ Ω cm) * (100 cm / 0.01 cm²)
R = (1.7 × 10⁻⁶) * (100 / 10⁻²) Ω
R = (1.7 × 10⁻⁶) * (10⁴) Ω
R = 1.7 × 10⁻² Ω
To convert Ohms to milli-Ohms, multiply by 1000:
R = 1.7 × 10⁻² Ω * 1000 milli-ohm/Ω
R = 1.7 × 10¹ milli-ohm
R = 17 milli-ohm