Heat and Mass Transfer

Fick's first law of molecular diffusion states that the molar flux $J_A$ is directly proportional to:

Options:

• (A) Concentration gradient $\frac{dC_A}{dx}$
• (B) Temperature gradient $\frac{dT}{dx}$
• (C) Velocity gradient $\frac{du}{dy}$
• (D) Pressure difference squared