Answer the following questions:(a) The earth’s magnetic field varies from point to point in space. Does it also change with time? If so, on what time scale does it change appreciably?(b) The earth’s core is known to contain iron. Yet geologists do not regard this as a source of the earth’s magnetism. Why?(c) The charged currents in the outer conducting regions of the earth’s core are thought to be responsible for earth’s magnetism. What might be the ‘battery’ (i.e., the source of energy) to sustain these currents?(d) The earth may have even reversed the direction of its field several times duringits history of 4 to 5 billion years. How can geologists know about the earth’s field in suchdistant past?(e) The earth’s field departs from its dipole shape substantially at large distances (greater than about 30,000 km). What agencies may be responsible for this distortion?(f ) Interstellar space has an extremely weak magnetic field of the order of 10−12 T. Can such a weak field be of any significant consequence? Explain.[Note: Exercise 5.2 is meant mainly to arouse your curiosity. Answers to some questionsabove are tentative or unknown. Brief answers wherever possible are given at the end. For details, you should consult a good text on geomagnetism.]

Answer the following questions:(a) The earth’s magnetic field varies

1.	Answer the following questions:(a) The earth’s magnetic field varies from point to point in space. Does it also change with time? If so, on what time scale does it change appreciably?(b) The earth’s core is known to contain iron. Yet geologists do not regard this as a source of the earth’s magnetism. Why?(c) The charged currents in the outer conducting regions of the earth’s core are thought to be responsible for earth’s magnetism. What might be the ‘battery’ (i.e., the source of energy) to sustain these currents?(d) The earth may have even reversed the direction of its field several times duringits history of 4 to 5 billion years. How can geologists know about the earth’s field in suchdistant past?(e) The earth’s field departs from its dipole shape substantially at large distances (greater than about 30,000 km). What agencies may be responsible for this distortion?(f ) Interstellar space has an extremely weak magnetic field of the order of 10−12 T. Can such a weak field be of any significant consequence? Explain.[Note: Exercise 5.2 is meant mainly to arouse your curiosity. Answers to some questionsabove are tentative or unknown. Brief answers wherever possible are given at the end. For details, you should consult a good text on geomagnetism.]
Answer» (a) Earth’s magnetic field changes with time. It takes a few hundred years to change by an appreciable amount. The variation in earth’s magnetic field with the time cannot be neglected. (b)Earth’s core contains molten iron. This form of iron is not ferromagnetic. Hence, this is not considered as a source of earth’s magnetism. (c)The radioactivity in earth’s interior is the source of energy that sustains the currents in the outer conducting regions of earth’s core. These charged currents are considered to be responsible for earth’s magnetism. (d)Earth reversed the direction of its field several times during its history of 4 to 5 billion years. These magnetic fields got weakly recorded in rocks during their solidification. One can get clues about the geomagnetic history from the analysis of this rock magnetism. (e)Earth’s field departs from its dipole shape substantially at large distances (greater than about 30,000 km) because of the presence of the ionosphere. In this region, earth’s field gets modified because of the field of single ions. While in motion, these ions produce the magnetic field associated with them. (f)An extremely weak magnetic field can bend charged particles moving in a circle. This may not be noticeable for a large radius path. With reference to the gigantic interstellar space, the deflection can affect the passage of charged particles.

Discussion

No Comment Found

Related InterviewSolutions

What is the difference between multimolecular and macromolecular collids ? Give one example of each . How are associated colloids different from these two types of colloids ?
Gastrointestinal irritation, cardiovascular effects, including tachycardia,arrhythmias, and orthostatic hypotension, mental disturbances, and withdrawalare possible adverse effects of: A. Amantadine B. Benztropine C. Levodopa D. selegiline
Match the column I and IIColumn-IColumn-II(a)Parasitism(i)++(b)Commensalism(ii)+ –(c)Amensalism(iii)0 + (d)Mutualism(iv)0 –(1) (a) - iii, (b) - ii, (c) - iv, (d) - i (2) (a) - i, (b) - ii, (c) - iii, (d) - iv (3) (a) - ii, (b) - iii, (c) - i, (d) - iv (4) (a) - ii, (b) - iii, (c) - iv, (d) - i
Assertion: In commensalism, one organism is benefitted and other is unaffected Reason: Cattle egret bird and cattle is an example of commensalism (1) If both assertion and reason are true and reason is the correct explanation of assertion. (2) If both assertion and reason are true but reason is not the correct explanation of assertion. (3) If assertion is true but reason is false. (4) If both assertion and reason are false.
In charge of Calcutta Mint between 1832 to 1838, he studied and deciphered Ashokan rocks and pillars. His essays on antiquities are considered as classics. Hint: Varanasi. Who are we referring to?
Nature of climax community depends upon(A) Climate (B) Water (C) Soil fertility (D) Temperature
How do biofertilisers enrich the fertility of the soil?
Read carefully the passage and select the correct answer out of given four options:Biofertilizers are organisms that enrich nutrient quality of the soil. The important sources of biofertilizers are bacteria, fungi and cyanobacteria. The symbiotic association of Rhizobium with the root nodules of leguminous plants is the common example. These bacteria convert atmospheric nitrogen into nitrogenous compound and fix in the soil.The organisms which enrich the nutrient quality of the soil are called(a) Microbes(b) Biofertilizers(c) Yeast(d) Biopesticides
Electrophoresis is an essential procedure that needs to be employed in genetic fingerprinting why?
Assertion: Angiosperms form endosperm after fertilization and is diploid. Reason: In gymnosperms, endosperm is formed before fertilization and is triploid. a. Both assertion and reason are true, and reason is the correct explanation of assertion. b. Both assertion and reason are true, but reason is not the correct explanation of assertion. c. Assertion is true but reason is false. d. Both assertion and reason are false.

Discussion

No Comment Found

Related InterviewSolutions

Reply to Comment