Step 1: Understanding the Concept:
Post-harvest cleaning and separation of agricultural seeds utilize differences in physical properties (such as size, density, shape, and surface texture) to segregate different species of grains.
Detailed Explanation:
- Analysis of Assertion (A): Mustard seeds are spherical, while wheat grains are elongated and flat.
The spiral separator is highly effective for separating mixtures containing spherical seeds and flat/irregular grains.
Therefore, Assertion (A) is true.
- Analysis of Reason (R): A spiral separator has no moving parts. It consists of a vertical central column surrounded by a spiral chute.
When a mixture is fed at the top, round seeds (like mustard) roll down the chute quickly. Centrifugal force pushes them to the outer edge of the spiral, where they are collected separately.
Flat, elongated, or irregular grains (like wheat) slide slowly along the inner edge of the chute due to friction.
Because the separator operates based on differences in shape and roundness, Reason (R) is true and correctly explains why the spiral separator is effective for this mixture.
Step 2: Final Answer:
Both (A) and (R) are true, and (R) is the correct explanation of (A), corresponding to option (1).