Question Detail
Question
The number of particles crossing unit area per unit time is N = −D (n₂−n₁)/(z₂−z₁). The dimensional formula for the diffusion constant D is:
Correct Answer
Option B is the correct answer.
Detailed Explanation
N is number per area per time, dimensions L⁻²T⁻¹. (n₂−n₁) is concentration difference, number per volume, dimensions L⁻³. (z₂−z₁) is length, dimensions L. So D = −N * (z₂−z₁)/(n₂−n₁). Dimensions: [D] = (L⁻²T⁻¹) * L / L⁻³ = L⁻²T⁻¹ * L⁴ = L²T⁻¹.
Hint
Solve for D and find dimensions.