What is resistance of the cable (resistivity of copper is1.7x10^-8)Answer is 14 ohms. But please explain how do we get there in full detail.
Resistance (R) of a wire is given by: R = ρ.L / A where (ρ) is the resistivity of the wire in Ω.m ; (A) is the cross sectional area of the cable in m? ; (L) is the length of the wire in metres. Radius (r) of one strand = (0.51 / 2) = 0.255 mm = 0.000255 m Cross sectional area of one strand = πr? = (π * 0.000255?) = 2.0428 x 10^-7 m? Total cross section of cable = (12 * 2.0428 x 10^-7 m?) = 2.45 x 10^-6 m? R = (1.7 x 10^-8 * 2000 / 2.45 x 10^-6) = 13.87 = 14 Ω to 2 significant figures.
Find total cross sectional area of copper in cable ie 12 * area of one. calculate the resistance of 1 m then multiply by 2000.
