An inductor coil of inductance 17 mH is constructed from a copper wire of length 100 m and cross - sectional are `1mm^2`. Calculate the time constant of the circuit if this inductor is joined across an ideal battery. The resistivity of copper =`1.7 X 10^(-8) Omega m.

Explanation

Here `L=17mH, l=100m`
`A=1 mm^(2)=1xx10^(-6)m^(2)`
`:. Fcv=1.7xx10^(-8) (Omega)-m`
`=(1.7xx10^(-2)xx100)/(1xx10^(-6))=1.7 (Omega)`
`i=(L/R)=(17xx10^(-3))/(17)`
`=10^(-2)Sec=10m sec.`