Q. 4 The resistivity of copper is 1.76 × 10¯⁸Ω m. The radius of the wire is 1mm. Calculate the length of a telegraph wire needd for having a resistance of 10.5Ω?

Q. 4 The resistivity of copper is 1.76 × 10¯⁸Ω m. The radius of the wire is 1mm. Calculate the length of a telegraph wire needd for having a resistance of 10.5Ω?