Question

Identify the correct pair(s) of governing law with respective process operation.

• A. Stoke’s law – Mass transfer
• B. Kirchhoff’s law – Radiation heat transfer
• C. Fourier’s law – Conduction heat transfer
• D. Fick’s law – Molecular diffusion

Hint:

Easy memory: - Kirchhoff → Radiation, - Fourier → Conduction, - Fick → Diffusion, - Stoke’s → Settling (not mass transfer).

Answer 1

The Correct Option is B, C, D

Step 1: Analyze each pair.
- (A) Incorrect. Stoke’s law deals with sedimentation/particle settling velocity, not mass transfer.
- (B) Correct. Kirchhoff’s law of thermal radiation states emissivity = absorptivity for a body in thermal equilibrium.
- (C) Correct. Fourier’s law describes heat conduction: \( q = -k \frac{dT}{dx} \).
- (D) Correct. Fick’s law defines molecular diffusion: \( J = -D \frac{dc}{dx} \).
Final Answer: \[ \boxed{\text{(B), (C), and (D)}} \]