Question

7. The length of a wire is 100 m and diameter 2 mm. Specific resistance of the material of the wire is 4.8 x 10-8 ohm-m. What will be the resistance of a wire made of the same material having the same mass but double diameter ?​

Answer 1

Answer:

Given :   R=0.07Ω        l=100 cm =1 m             d=2 mm =0.002 m

Using      R=ρ(π/4)d2l

∴    0.07=ρ(π/4)(0.002)21                 ⟹  ρ=22×10−6  Ω m