Question

Find the resistance of a piece of a piece of wire 100cm long and area of cross section 0.25 mm 2 . Resistivity of the material of the wire is 10 -6 Ωm.

Answer 1

resistance=resistivity * length / Area
CONVERT ALL THE TERMS IN SI UNITS FIRST

(100cm=1m)
(0.25mm^2 = 0.25 * 10^-6 m^2)

By substituting the values above in the formula we get...

resistance = 10^-6 *1 / 0.25*10^-6
the 10^-6 terms get canceled and we are left with

1/0.25 = 4ohms

so resistance = 4 ohms

Answer 2

Explanation:

here is your ans.............