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 number of particles per unit volume for the value of `x` meant to `x_(2)` and `x_(1)`. Find dimensions of `D` called as diffusion constant

Options

A. `[M^(0)L^(2)T^(-1)]`
B. `[ML^(2)T^(-1)]`
C. `[MLT^(-1)]`
D. None of these

Answer

A

Explanation

`N= -D(n_(2)-n_(1))/(z_(2)-z_(1))`
`implies [N]= [D]([n_(2)-n_(1)])/([z_(2)-z_(1)])`
`implies [L^(-2)T^(-1)]=[D]([L^(-3)])/([L])`
`implies [D]= [L^(2)T^(-1)]`
`implies [D]=[M^(0)L^(2)T^(-1)]`.