Evaluate: Statement 1 — Due to curvature of the Earth, an object appears at a lower position than its true position. Statement 2 — Due to atmospheric refraction, the object appears at a higher position.
Correct Answer: C. Both statements are correct
📚 Detailed Explanation: Both Statements Correct (Curvature Lowers; Refraction Raises Apparent Object)
Why C (Both statements are correct) is correct: (1) Due to Earth's curvature, the staff appears shifted downward relative to the true level line — i.e., the object appears at a lower apparent position. (2) Due to atmospheric refraction, the light ray bends downward, making the object appear higher than it actually is. Both effects act simultaneously and are combined as C = 0.0673D².
Curvature and Refraction: Individual Effects
| Effect | Physical Cause | Effect on Observed Staff Reading | Effect on Apparent Position of Object |
|---|---|---|---|
| Earth curvature | Ground curves away below the horizontal line of sight | Staff reading appears too large (read a higher number than the true one) | Object (ground) appears lower than it truly is |
| Atmospheric refraction | Light bends downward through denser lower atmosphere | Partially reduces the curvature effect (makes reading appear smaller again by 1/7) | Object appears higher than without refraction (compensates curvature partially) |
| Net combined effect | Curvature dominates (6/7 of curvature remains) | Reading still appears too large by 0.0673D² | Object still appears lower than true |
Statement 1: “Due to curvature, the object appears lower” — CORRECT (the ground curves away; you have to look “down more” than the true horizontal to see the object).
Statement 2: “Due to refraction, the object appears higher” — CORRECT (bent light makes you see the object as if it were higher than it is).
Both statements are correct → option C.
Statement 2: “Due to refraction, the object appears higher” — CORRECT (bent light makes you see the object as if it were higher than it is).
Both statements are correct → option C.
- Curvature: ground curves away → object appears lower than true position.
- Refraction: light bends downward → object appears higher than true position (partial correction).
- Net effect: combined correction 0.0673D² (curvature dominant; object still appears lower overall).