Consider a thin square sheet of side L and thickness t, made of a material of resistivity `rho`. The resistance between two opposite faces, shown by the shaded areas in the figure is

Options

A. directly proportional to L
B. directly proportional to t
C. independent of L
D. independent of t

Answer

C

Explanation

(c) We know that `R = rho l/a`
where l is the length of
the conductor through
which the current flows
and a is the area of cross
section.
Here `l = L and a = L xx t `
`:. R = (rhoL)/(Lxxt) = rho/t`
`:. R is independent of L .