Question

a copper wire has diameter of 0.5 mm and resistivity of 1.6 ×10^ -8 ohm meter .what will be the length of wire to make its resistence 10 ohm​

Answer 1

Answer:

The resistance of a cylindrical wire, as a function of the resistivity Rho is :

R = Rho x L / S

Expressed according to the volume, we obtain:

R = Rho x L ^ 2 / V

At constant volume, the stretch doubling the initial length, it comes :

Final R = Rho x (2 x L ^ 2) ^ 2 / V

Final R = 4 x R

So, final R = 4 x 4 = 16 ohms