Question

Find the length of nichrome wire of resistivity 100 ×10^-6ohm of area of cross section 1mm square to yield a resistance of 10 ohm. ​

Answer 1

given ρ= 100 x 10*10-6 ohm=10 A=1mm to convert into metre soA= 10*-3

formula for resistivity is ρ=(RA/L)

L=RA/ρ

=10x10*-3/100x10*-6

=10*-3/10x10*-6

=10*-3/10*-5

=10*15

therfore length of the nichrome is 10*15