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The earth may have been reversed the dir...

The earth may have been reversed the direction of its field several times during its history of 4 to 5 billion years. How can geologists know about the earth's field in such distant past ?

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Earth's magnetic field gets recorded weakly in certain rocks during their solidification. An analysis of these rocks may reveal the history of earth's magnetism.
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A short bar magnet of magnetic moment 5.25 xx 10^(-2) JT^(-1) is placed with its axis perpendicular to the earth's field direction. At what distance from the centre of the magnet, the resultant field is inclined at 45^(@) with earth's field on (a) Its normal bisector and (b) its axis. Magnitude of the earth's field at the place is given to be 0.42 G. Ignore the length of the magnet in comparison to the distances involved.

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A short bar magnet of magnetic moment 0,21 A - m^(2) is placed with its axis perpendicular to the direction of the horizontal component of the earth 's magnetic field .The distance of the point on the axis of the magnet from the centre of the magnet where the resultant magnetic field is inclined at 45^(@) with the horizontal component of the earth's field direction is (horizontal component of the earth's magnetic field 4.2xx10^(-5)

An electron falls through a distance of 1.5 cm in a uniform electric field of magnitude 2.0xx10^(4) N C^(-1) . The direction of the field is reversed keeping its magnitude unchanged and a proton falls through the same distance. Compute the time of fall in each case. Contrast the situation with that of 'free fall under gravity'.

A square loop of side 12 cm with its sides parallel to X and velocity of 8 cm s in the positive x-direction in an environment containing a magnetic field in the positive z-direction. The field is neither uniform in space nor constant in time. It has a gradient of 10 T cm along the negative x-direction (that is it increases by 103 T cm- as one moves in the negative x-direction), and it is decreasing in time at the rate of 103 Ts. Determine the direction and magnitude of the induced current in axes is moved with a the loop if its resistance is 4.50 m2. Sol. Given, side of loop a = 12 cm . Area of loop (A) = a = (12) = 144 cm = 144 x 10 m? (. Area of square = (side))

VIKRAM PUBLICATION ( ANDHRA PUBLICATION)-MAGNETISM AND MATTER-Textual Exercises
  1. The earth's core is known to contain iron. Yet geologists do not rega...

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  2. The charged currents in the outer conducting regions of the earth's co...

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  3. The earth may have been reversed the direction of its field several ti...

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  4. The earth's field departs fromits dipole shape substantially at large ...

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  5. Interestellar space has an extremely weak magnetic field of the order ...

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  6. A short bar magnet placed with its axis at 30^(@) with a uniform exter...

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  7. A short bar magnet of magnetic moment m= 0.32 J T^(-1) is placed in a ...

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  8. A closely wound solenoid of 800 turns and area of cross section 2.5 xx...

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  9. If the solenoid is free to turn about the vertical direction and a uni...

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  10. A bar magnet of magnetic moment 1.5 JT^(-1) lies aligned with the dire...

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  11. A bar magnet of magnetic moment 1.5 JT^(-1) lies aligned with the dire...

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  12. A closely wound solenoid of 2000 turns and area of cross-section 1.6 x...

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  13. A closely wound solenoid of 2000 turns and area of cross-section 1.6 x...

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  14. A circular coil of 16 turns and radius 10 cm carrying a current of 0.7...

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  15. A magnetic needle free to rotate in a vertical plane parallel to the m...

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  16. At a certain location in Africa, a compass points 12^(@) west of the g...

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  17. A short bar magnet has a magnetic moment of 0.48 JT^(-1). Give the dir...

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  18. A short bar magnet placed in a horizontal plane has its axis aligned a...

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  19. A short bar magnet placed in a horizontal plane has its axis aligned a...

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  20. A short bar magnet of magnetic moment 5.25 xx 10^(-2) JT^(-1) is place...

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