Multiple choice

Determine the correctness or otherwise of the following Assertion [a] and the Reason [r]. Assertion [a]: Curvature correction must be applied when the sights are long. Reason [r]: Line of collimation is not a level line but is tangential to the level line.

  1. Both [a] and [r] are true and [r] is the correct reason for [a].

  2. Both [a] and [r] are true but [r] is not the correct reason for [a].

  3. Both [a] and [r] are false.

  4. [a] is false but [r] is true.
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A Correct answer
Explanation

Curvature correction is necessary because the earth's surface is curved, and the line of sight (collimation) is tangential to the level surface, causing a vertical divergence over long distances.

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