Question

Given below are two statements:
Statement (I): Penman proposed an equation for evaporation from an open water surface based on a combination of energy balance and sink strength.
Statement (II): For converting PET into ET, suitable crop coefficients should be evolved for different crops, soils and climatic conditions, and also for different stages of growth for the same crop.
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both Statement (I) and Statement (II) are correct.
• B. Both Statement (I) and Statement (II) are incorrect.
• C. Statement (I) is correct but Statement (II) is incorrect.
• D. Statement (I) is incorrect but Statement (II) is correct.

Hint:

Recall that Penman's method blends two approaches, and that crop coefficients are never a single universal number.

Answer 1

The Correct Option is A

Check each statement against how the Penman method and crop coefficients actually work.
Penman's method is well known precisely because it does not rely on one physical approach alone; it blends the energy balance equation with the aerodynamic term that represents the vapour removing power of the wind, sometimes called sink strength. That is exactly Statement (I), so it holds.
For Statement (II), the standard practice in irrigation scheduling is ET = Kc times PET, and Kc is never a single fixed number; it is built up separately for each crop, adjusted for local soil and climate, and further varies through the crop growth stages (initial, development, mid season, late season). This is precisely what Statement (II) claims.
Since both descriptions line up with standard practice,
\[\boxed{\text{Both Statement (I) and Statement (II) are correct, option 1}}\]