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प्रश्न
The earth’s core is known to contain iron. Yet geologists do not regard this as a source of the earth’s magnetism. Why?
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उत्तर
Earth’s core contains molten iron. This form of iron is not ferromagnetic. Hence, this is not considered a source of earth’s magnetism.
संबंधित प्रश्न
A compass needle which is allowed to move in a horizontal plane is taken to a geomagnetic pole. It ______.
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The horizontal component of the earth's magnetic field at a place is `1/sqrt(3)` time the vertical component. Determine the angle of dip at that place.
Answer the following question in detail.
How does the magnetic declination vary with latitude? Where is it minimum?
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.
A magnetic needle free to rotate in a vertical plane parallel to the magnetic meridian has its north tip pointing down at 22° with the horizontal. The horizontal component of the earth’s magnetic field at the place is known to be 0.35 G. Determine the magnitude of the earth’s magnetic field at the place.
At a certain location in Africa, a compass points 12° west of the geographic north. The north tip of the magnetic needle of a dip circle placed in the plane of magnetic meridian points 60° above the horizontal. The horizontal component of the earth’s field is measured to be 0.16 G. Specify the direction and magnitude of the earth’s field at the location.
A short bar magnet placed in a horizontal plane has its axis aligned along the magnetic north-south direction. Null points are found on the axis of the magnet at 14 cm from the centre of the magnet. The earth’s magnetic field at the place is 0.36 G and the angle of dip is zero. What is the total magnetic field on the normal bisector of the magnet at the same distance as the null point (i.e., 14 cm) from the centre of the magnet? (At null points, field due to a magnet is equal and opposite to the horizontal component of earth’s magnetic field.)
A short bar magnet of magnetic moment 5.25 × 10−2 J T−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.
Which of the following statements about earth's magnetism is correct?
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The net magnetic flux through any closed surface, kept in a magnetic field is ______.
The horizontal component of earth’s magnetic field at a place is `sqrt3` times the vertical component. The angle of dip at that place is ______.
The small angle between magnetic axis and geographic axis at a place is ______.
The vertical component of earth's magnetic field is zero at a place where angle of dip is
At a place of latitude 5°, angle of dip is nearly
The angle between the magnetic meridian and geographical meridian is called ______
Isogonic lines are those for which ______.
Consider the plane S formed by the dipole axis and the axis of earth. Let P be point on the magnetic equator and in S. Let Q be the point of intersection of the geographical and magnetic equators. Obtain the declination and dip angles at P and Q.
The earth's magnetic field lines resemble that of a dipole at the centre of the earth. If the magnetic moment of this dipole is close to 8 × 1022 Am2, the value of earth's magnetic field near the equator is close to ______. (radius of the earth = 6.4 × 106 m)
