Soil Science - Study Mode

[#811] The law of the minimum was given by Liebig in
Correct Answer

(A) 1862

Explanation

Solution: The law of the minimum was given by Liebig in 1862. This law states that the growth is dictated not by total resources available, but by the scarcest resource which is also referred to as a limiting factor. It was found that increasing the number of plentiful nutrients did not increase the plant growth, only by increasing the amount of the limiting nutrient, did the growth of the crop was improved.

[#812] Most microorganism function at their best within a pH range
Correct Answer

(A) 6.0 - 7.5

Explanation

Solution: Most of the microorganisms function at their best within the neutral pH range i.e. of 6.0 - 7.5 . The pH is important for the proper functioning of organisms as the enzymes that catalyze the chemical reactions of life require a specific pH to function. Moreover, the increase and decrease in pH can cause denaturation of biochemical like proteins and make them non-functional, resulting in cell death.

[#813] Azomethine H is used for determination of
Correct Answer

(A) B

Explanation

Solution: Azomethine H is a colorimetric reagent for the determination and detection of Boron. It forms an orange complex with boron in an aqueous solution. The molar absorptivity of this complex is 1.01 × 10 4 at 415 nm which can be further detected in the range of 1 - 6 micrograms per ml.

[#814] Match the following columns: Column I (Soil Type) Column II (Characteristic) a. Entisol 1. Clay rich soil b. Vertisol 2. Highly weathered tropical and subtropical soil c. Spodosol 3. Young soils with no horizon d. Oxisol 4. Acid soils with leached upper horizon
Correct Answer

(B) a-3, b-1, c-4, d-2

Explanation

Solution: Entisols are the young soils with no horizon. These are the most abundant soil order, occupying about 16% of the global ice-free land area. Vertisols are clay-rich soil. The high content of clay minerals shrinks and swells as they change water content. Spodosols are acid soils with the leached upper horizon and are characterized by an accumulation of humus that is complexed with aluminium and Iron. Oxisol is highly weathered tropical and subtropical soil. These are found primarily in the intertropical regions of the world.

[#815] Dry Ice sublimes at which temperature?
Correct Answer

(D) -78°C

Explanation

Solution: Dry ice is a solid form of carbon dioxide. It is commonly used for temporary refrigeration as carbon dioxide does not have a liquid state at atmospheric pressure and sublimates directly from the solid-state to the gas state. It is primarily used as a cooling agent. Dry ice sublimes at -78°C (194.7 K) at the earth's atmospheric pressure.