UPSC Prelims 2012 · Question 20 of 98
UPSC Prelims 2012 question on Earth Magnetic Field Charged Particles
- ExamUPSC CSE
- Year2012
- PaperGeneral Studies Paper I
- SubjectGeography
- TopicClimatology
- DifficultyHard
- TypeDirect
Electrically charged particles from space travelling at speeds of several hundred km/sec can severely harm living beings if they reach the surface of the Earth. What prevents them from reaching the surface of the Earth?
Show answer
Answer: A. The Earth’s magnetic field diverts them towards its poles.
Verdict
Correct Answer: The Earth’s magnetic field diverts them towards its poles
Analysis
High-speed charged particles from the Sun are mainly protons and electrons carried by the solar wind. Earth is protected from them largely by its magnetic field.
1. The Earth’s magnetic field diverts them towards its poles — Correct
Earth’s magnetic field acts as a protective shield against charged particles from the Sun.
These particles are deflected by the magnetic field and many are guided towards the polar regions, where they interact with the upper atmosphere and produce auroras.
2. The ozone layer protects against them — Incorrect
The ozone layer mainly protects Earth from harmful ultraviolet radiation.
It does not primarily protect against high-speed charged particles like protons and electrons.
3. Moisture in the atmosphere stops them — Incorrect
Water vapour does not have the required electromagnetic shielding effect.
It cannot effectively stop or divert high-energy charged particles from the Sun.
Extra UPSC info
* Solar wind is a stream of charged particles released from the Sun.
* Earth’s magnetic field forms the magnetosphere, which shields the planet from many charged particles.
* Some particles get trapped in the Van Allen radiation belts.
* Auroras occur when charged particles interact with gases in the upper atmosphere near the poles.
* Coronal Mass Ejections can trigger geomagnetic storms.
* Geomagnetic storms may disturb satellites, GPS, radio communication and power grids.
How to crack it
Earth is protected from high-speed solar charged particles mainly because its magnetic field diverts them towards the poles, not because of the ozone layer or atmospheric moisture.