Question

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: In offset disc harrow the couple acting on front gang is considerably smaller than that of rear gang.
Reason R: In off-set disc harrow the rear gang is operating in loose soil compared to front gang.
In light of the above statements, choose the correct answer from the options given below

• A. Both A and R are true and R is the correct explanation of A
• B. Both A and R are true but R is NOT the correct explanation of A
• C. A is true but R is false
• D. A is false but R is true

Hint:

To analyze disc harrows, remember:
- Front Gang: Works in firm, untilled soil (higher draft, larger forces).
- Rear Gang: Works in loose, pre-tilled soil (lower draft, smaller forces).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
An offset disc harrow consists of two gangs of discs angled in opposite directions.
The front gang cuts and moves the soil in one direction, while the rear gang cuts and moves it back in the opposite direction.
Detailed Explanation:
Let us analyze Assertion A:
As the tractor moves forward, the front gang cuts into hard, undisturbed, compact soil.
This results in high soil resistance and draft forces.
The rear gang, by contrast, follows behind and operates on soil that has already been cut and loosened by the front gang.
Because the soil is looser, the forces acting on the rear gang are lower.
Therefore, the forces and the resulting rotational moment (couple) acting on the front gang are significantly larger, not smaller, than those acting on the rear gang.
Thus, Assertion A is false.
Let us analyze Reason R:
The front gang acts as the primary cutting tool, breaking up the firm ground.
The rear gang operates in this newly loosened soil, which improves pulverization and mixes the soil.
Thus, the rear gang operates in looser soil than the front gang.
Therefore, Reason R is true.

Step 2: Final Answer:
Assertion A is false, but Reason R is true.