The resistance of a wire of 0.01 cm radius is 10`Omega`. If the resistivity of the material of the wire is 50 `xx 10^(-8)` ohm meter, find the length of the wire.

Explanation

Given Radius `= 0.01 cm = 0.01 xx10^(-2) ` m .
Resistivity `rho =50xx10^(-8) Omega` m.
Resistance R =` 10 Omega`
`R = rho (l)/(A) =rho (l)/(pir^(2))`
`l= (Rpir^(2))/(rho)`
`(10xx3.14xx0.01xx10^(-2)xx0.01xx10^(-2))/(50xx10^(-8))`
`=(314xx10^(-4))/(50xx10^(-8)xx10^(5))`
Length =`(6.28xx10^(-4))/(10^(-3))` =0.628 m .