The resistivity of copper is 1.7 X 1O^-8 ohm m. What length of copper wire of diameter 0.1 mm will have a resistance of 34 ohm?
1 Answer
Apr 29, 2018
Resistance
#R=rhol/A#
where#rho# is resistivity or specific resistance of the material of the conductor.
Inserting given values in the expression in SI units we get
#34=(1.7 xx 10^-8)l/(pi(0.1/(1000))^2/4)#
#=>l=34/(1.7 xx cancel(10^-8))xxpi/4cancel((0.1/(1000))^2)#
#=>l=15.71\ m# , rounded to two decimal places.