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A : In earn may nave even reversea the d...

A : In earn may nave even reversea the direction of its field several time during its history of 4 to 5 billion years.
R: Earth's magnetic field gets weakly' recorded' in certain rocks during solidification.

A

If both Assertion & Reason are the true and the reason is the correct explanation of the assertion, then mark (1)

B

If both Assertion & Reason are true but the reson is not the correct explanation of the assertion, then mark (2)

C

If Assertion is true statement but Reason is false, then mark (3)

D

If both Assertion and Reason are false statements, then mark (4)

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The correct Answer is:
To analyze the given statements about Earth's magnetic field and its historical reversals, we can break down the reasoning step by step. ### Step-by-Step Solution: 1. **Understanding the Assertion:** - The assertion states that the Earth may have reversed the direction of its magnetic field several times during its history of 4 to 5 billion years. This phenomenon is known as "geomagnetic reversal." - Geomagnetic reversals are documented occurrences where the magnetic north and south poles switch places. 2. **Understanding the Reason:** - The reason provided states that Earth's magnetic field gets weakly recorded in certain rocks during their solidification. - When magma cools and solidifies into rock, magnetic minerals within the rock can align themselves with the Earth's magnetic field at that time. This creates a record of the magnetic orientation at the time of solidification. 3. **Connecting Assertion and Reason:** - The assertion is supported by the reason because the recording of the magnetic field in rocks allows scientists to study the history of geomagnetic reversals. - By examining the orientation of magnetic minerals in various rock layers, researchers can determine when reversals occurred and how often they have happened over geological time. 4. **Conclusion:** - Both the assertion and the reason are correct. The assertion accurately describes the phenomenon of geomagnetic reversal, and the reason explains how this phenomenon can be studied through geological records. ### Final Answer: Both assertion (A) and reason (R) are correct, and R explains A. ---
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AAKASH INSTITUTE ENGLISH-MAGNETISM AND MATTER -ASSIGNMENT (SECTION D)
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  2. A: A system can have magnetic moments even though its net charge is ze...

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  3. A: The earth's magnetic field not only varies from point to point in s...

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  4. A : In earn may nave even reversea the direction of its field several ...

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  5. A: The earth's field departs from its dipole shape substantially at la...

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  6. A: Paramagnetic sample displays greater magnetisation (for the magneti...

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  7. A: Diamagnetism is almost indipendent of temperature. R: The induced...

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  8. A: If a toroid uses bismuth for its core, then the field in the core w...

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  9. A: Peramability of a ferromagnetic material is independent of the magn...

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  10. A: The maximum possible magnetization of a paramagnetic sample is of t...

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  11. A: Peramability of a ferromagnetic material is independent of the magn...

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  12. A charged particle is released from rest in a region of steady and uni...

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  13. A: magnetic field lines are continuous and form closed loops. R: Mag...

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  14. Assertion : A superconductor is a perfect diamagnetic substance. Rea...

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  15. A: Superconducting magnets are gainfully exploited in running magnetic...

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  16. A: Diamagnetism is exhibited by all the substances. R: Diamagentism ...

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  17. A: Above curie-point a ferromagnetic substance behaves as a paramagnet...

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  18. A: Earth's magnetism protects us from many of thte harmful cosmic rays...

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  19. A: In a diamagnetic substance each atom has a non-zero dipole moment b...

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  20. A: The magnetic field lines have a tendency to avoid entering the body...

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