Altitude of a geostationary satellite relative to Earth’s surface The distance of a geostationary (synchronous, equatorial) satellite from Earth’s surface is approximately how many kilometres?
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A300
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B10,000
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C35,900
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D5
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E22,300
Answer
Correct Answer: 35,900
Explanation
Introduction / Context:Geostationary satellites orbit with a period equal to Earth’s rotational period and remain fixed relative to a point on the equator. Their altitude is set by orbital mechanics.
Given Data / Assumptions:
- Geostationary orbit radius from Earth’s center ≈ 42,164 km.
- Mean Earth radius ≈ 6,378 km.
Concept / Approach:Altitude above Earth’s surface = orbital radius − Earth’s mean radius ≈ 42,164 − 6,378 ≈ 35,786 km. Rounded values in practice are often quoted as ~35,800–35,900 km.
Step-by-Step Solution:R_orbit ≈ 42,164 km.R_Earth ≈ 6,378 km.Altitude ≈ 42,164 − 6,378 ≈ 35,786 km.Closest listed choice ≈ 35,900 km.
Verification / Alternative check:Standard references list geostationary altitude at about 35,786 km; engineering texts commonly round to ~35,800–35,900 km.
Why Other Options Are Wrong:300 km and 10,000 km correspond to low-Earth and medium-Earth regimes; 5 km is nonsensical; 22,300 km is miles (≈ 22,300 miles ≈ 35,900 km), not kilometres.
Common Pitfalls:Confusing miles and kilometres; ensure consistent units.
Final Answer:35,900