Question

A copper wire has diameter of 0.5 mm and resistivity of 1.6 into 10 to the power minus 6 ohm cm how much of this wire would be required to make a 10 ohm coil

Answer 1

r = 0.25×10^-3 m
A = 3.14× 0.25 × 10^-3 = 0.785 m^2
p = -6 × 10^-2
R = 10 ohm

R = p _l_
A
10 = -6×10^-2 × _l_
0.785 × 10^-3
10 = -7.64 × 10 × l
l = 1/-7.64
l = 1.303 m