UPSC Prelims 2005 Q17: Science & Technology – Computer & Information Technology
Consider the following statements :
1. A geostationary satellite is at an approximate height of 10,000 km
2. FM transmission of music is of very good quality because the atmospheric or man - made noises
which are generally frequency variations can do little harm.
Which of the statements given above is/are correct?
- (a) 1 only
- (b) 2 only
- (c) Both 1 and 2
- (d) Neither 1 nor 2
Answer: (b) 2 only
Explanation
Geostationary satellite and FM transmission
| Statement | Verdict |
|---|---|
| 1. Geostationary satellite is at about 10,000 km | False: it is at about 36,000 km above the equator |
| 2. FM is of good quality because noise is amplitude-based | True — noise mostly changes amplitude, and FM carries information in frequency |
Only statement 2 is correct.
Answer: (b) 2 only.
Why each option is right or wrong
- (a) Incorrect. The geostationary orbit is about 36,000 km, not 10,000 km.
- (b) CORRECT. Only statement 2 is correct.
- (c) Incorrect. Statement 1 is false.
- (d) Incorrect. Statement 2 is true.
Key point
Geostationary orbit: about 35,786 km, period 24 h, over the equator.
Remember
Geostationary satellites orbit at about 36,000 km.
Common mistakes
- Quoting 10,000 km instead of 36,000 km.
- Mixing up LEO (about 800 km) with geostationary.
- Confusing AM and FM noise behaviour.
Exam tip
FM is less noisy than AM; AM travels farther by sky wave.
Sources
- NCERT Class XII Physics — Communication Systems
- NCERT Class XI Physics — Gravitation (satellites: geostationary orbit)
- Indian Space Research Organisation — INSAT and GSAT: geostationary satellite systems