Question

Match List I with List II

Choose the correct answer from the options given below:

• A. A - II, B - IV, C - III, D - V
• B. A - II, B - IV, C - I, D - III
• C. A - II, B - IV, C - I, D - V
• D. A - II, B - III, C - I, D - V

Hint:

Water Flow $\rightarrow$ Darcy.
Particle Settling $\rightarrow$ Stokes.
Gas Diffusion $\rightarrow$ Fick.
Heat/Radiation $\rightarrow$ Wien.
Knowing these "Father Laws" of physical sciences is essential for soil physics exams.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks to match specific physical phenomena related to soil science and physics (List I) with the fundamental scientific laws that govern them (List II).
Detailed Explanation:

• A - Saturated flow in soil (II. Darcy's Law):
Henry Darcy formulated that the rate of water flow through a porous medium is directly proportional to the hydraulic gradient.
Equation: \( q = -K \frac{dh}{dl} \).

• B - Soil textural analysis (IV. Stokes Law):
In the pipette or hydrometer method of textural analysis, the size of particles (sand, silt, clay) is determined based on their terminal velocity when settling in water.
Stokes Law states that the velocity of a falling sphere is proportional to the square of its radius.

• C - Wavelength of emitted radiation (I. Wien's Law):
Wien's Displacement Law states that the wavelength of maximum emission from a blackbody is inversely proportional to its absolute temperature.
Equation: \( \lambda_{max} = b/T \).

• D - Diffusive flux of gas (V. Fick's Law):
Fick's first law of diffusion states that the flux of a gas (like $CO_2$ or $O_2$ in soil) is proportional to the concentration gradient.
Equation: \( J = -D \frac{dc}{dx} \).

Step 2: Final Answer:
The correct matching is: A-II, B-IV, C-I, D-V.