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UPSC 2011: A layer in the Earth’s atmosphere called Ionosphere facilitates radio communication. Why? 1. The presence of ozone causes the reflection of radio waves to Earth. 2. Radio waves have a very long wavelength. 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
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Not attemptedCorrect Answer: (d) Neither 1 nor 2
Radio waves are reflected by the ionosphere because it is a layer rich in charged ions and free electrons; ozone—which is concentrated in the stratosphere—has no role in this reflection. Although many radio waves are long-wavelength, length alone does not cause reflection; the critical factor is their frequency relative to the plasma frequency of the ionised layer. Therefore neither statement is correct. ([cdn-images.prepp.in](https://cdn-images.prepp.in/public/image/UPSC_CSE_Prelims_Paper_1_General_Studies_Question_Paper_June_12_2011__311eb06a334890d742f0a28a3ba5cc9f.pdf))
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Frequently Asked Questions
What is the correct answer to this UPSC 2011 Geography question?▼
The correct answer is option (d): Neither 1 nor 2. Watch the detailed video explanation in our Sherlocking Prelims course on UnlockIAS.
Which year was this Atmosphere & Climatology question asked in UPSC Prelims?▼
This question was asked in UPSC CSE Prelims 2011, GS Paper 1, as Question 27. It falls under Geography > Atmosphere & Climatology.
What is the difficulty level of this UPSC question?▼
This question is rated "moderate". It requires sound conceptual understanding of the topic.
How many UPSC Prelims questions have been asked from Atmosphere & Climatology?▼
UPSC has asked 70 questions from Atmosphere & Climatology (under Geography) across multiple years. Visit the topic page to see the full list and year-wise trends.