Calculate the resistance of 2 km long copper wire of radius 2 mm. (Resistivity of copper = 1.72 x 1 0-8)
Answers
Answer:
1.37 ohm
Explanation:
R = p×l/A
R stands for resistance
l for length and A for area while rho (p) for resistivity
p=1.72×10^-8 OHM - M
l=2km= 1000m
r = 2mm=2×10^-3 m
area if circle = pie × r^2
= 22/7×4×10^-6
putting all the values
1.72×10^-8×1000×7/22×4×10^-6
= 1.37 ohm
Answer:
Given,
radius of wire (r) = 2 mm = 2 × 10-³ m
Length of wire (L) = 2Km = 2 × 10³ m
resistivity of copper wire(P) = 1.72 × 10^-8 Ohm. m
use formula ,
R = pL/A
where , R is resistance
p is resistivity of wire and A is cross section area of wire .
A = πr² = 3.14 × (2 × 10-³)²
= 3.14 × 4 × 10^-6 m²
= 12.56 × 10^-6 m²
R = 1.72 × 10^-8 × 2 × 10³/12.56 × 10^-6
= { 1.72× 2 /12.56} × 10^(-8+3 +6)
= 1.72 × 2 × 10/12.56
= 34.4/12.56
=2.7388 Ohm
hence, resistance of copper wire = 2.74 Ohm