The number of particles is given by `n = -D(n_(2) - n_(1))/( x_(2) - x_(1))` crossing a unit area perpendicular to X - axis in unit time , where `n_(1)and n_(2)` are particles per unit volume for the value of `x` meant to `x_(2) and x_(1)` . Find the dimensions of `D` called diffusion constant.

Options

A. `[M^(0) L T^(-2)]`
B. `[M^(0) L^(2) T^(-4)]`
C. `[M^(0) L^(2) T^(-2)]`
D. `[M^(0) L^(2) T^(-1)]`

Answer

D

Explanation

` n = -(D(n_(2)-n_(1)))/(x_(2)-x_(1)) rArr T^(-1) L^(-2) = ( D(L^(-3)))/(L) rArr D = (T^(-1)L^(-2) xx L)/(L^(-3))`
`rArr D = [ M^(0) L^(2) T^(-1)]`