The resistivity of a material with resistance 200 ohm, length 10m and area twice that of the length is

A)
200
B)
300
C)
400
D)
500

Correct Answer : Option (C) :   400


Explanation : Resistance calculated from Ohm’s law and Stoke’s theorem will be R = ρL/A. To get resistivity, ρ = RA/L = 200 X 20/10 = 400.