Question

A copper wire has a diameter 0.5 mm and of 1.6 ×10^-8 ohm m.whatwill be the length of this wire to make its resistance 10 ohm ? How much does ots resistance change if the diameter is doubled ?

Answer 1

R = pl/A
so, l = R*A/p
= 10* pi* (0.25 *10^-3)^2 / (1.6* 10^-8)