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प्रश्न
Answer the following question in detail.
How does the magnetic declination vary with latitude? Where is it minimum?
उत्तर
Magnetic declination varies with location and over time. As one moves away from the true north the declination changes depending on the latitude as well as the longitude of the place. By convention, declination is positive when the magnetic north is east of true north, and negative when it is to the west. The decline is small in India. It is 0° 58′ west at Mumbai and 0° 41′ east at Delhi.
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संबंधित प्रश्न
The horizontal component of the earth’s magnetic field at a place is B and angle of dip is 60°. What is the value of vertical component of earth’s magnetic field at equator?
Where on the surface of Earth is the angle of dip zero?
A compass needle which is allowed to move in a horizontal plane is taken to a geomagnetic pole. It ______.
What is the angle of dip at a place where the horizontal component `(B_H)` and vertical component `(B_V)` of earth’s magnetic field are equal :
Choose the correct option.
The horizontal and vertical component of magnetic field of Earth are same at someplace on the surface of Earth. The magnetic dip angle at this place will be
Choose the correct option.
A place where the vertical components of Earth's magnetic field is zero has the angle of dip equal to
Choose the correct option.
A place where the horizontal component of Earth's magnetic field is zero lies at
What is a geographic meridian?
What happens to the angle of dip as we move towards magnetic pole from magnetic equator?
Solve the following problem.
A magnet makes an angle of 45° with the horizontal in a plane making an angle of 30° with the magnetic meridian. Find the true value of the dip angle at the place.
Answer the following question regarding earth’s magnetism:
A vector needs three quantities for its specification. Name the three independent quantities conventionally used to specify the earth’s magnetic field.
Answer the following question regarding earth’s magnetism:
If you made a map of magnetic field lines at Melbourne in Australia, would the lines seem to go into the ground or come out of the ground?
Answer the following question regarding earth’s magnetism:
In which direction would a compass free to move in the vertical plane point to, if located right on the geomagnetic north or south pole?
Answer the following question regarding earth’s magnetism:
Geologists claim that besides the main magnetic N-S poles, there are several local poles on the earth’s surface oriented in different directions. How is such a thing possible at all?
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?
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.
A long straight horizontal cable carries a current of 2.5 A in the direction 10° south of west to 10° north of east. The magnetic meridian of the place happens to be 10° west of the geographic meridian. The earth’s magnetic field at the location is 0.33 G, and the angle of dip is zero. Locate the line of neutral points (ignore the thickness of the cable)? (At neutral points, magnetic field due to a current-carrying cable is equal and opposite to the horizontal component of earth’s magnetic field.)
A telephone cable at a place has four long straight horizontal wires carrying a current of 1.0 A in the same direction east to west. The earth’s magnetic field at the place is 0.39 G, and the angle of dip is 35°. The magnetic declination is nearly zero. What are the resultant magnetic fields at points 4.0 cm below the cable?
A compass needle free to turn in a horizontal plane is placed at the centre of circular coil of 30 turns and radius 12 cm. The coil is in a vertical plane making an angle of 45° with the magnetic meridian. When the current in the coil is 0.35 A, the needle points west to east.
(a) Determine the horizontal component of the earth’s magnetic field at the location.
(b) The current in the coil is reversed, and the coil is rotated about its vertical axis by an angle of 90° in the anticlockwise sense looking from above. Predict the direction of the needle. Take the magnetic declination at the places to be zero.
The angle of dip at a certain place where the horizontal and vertical components of the earth’s magnetic field are equal is ______.
The vertical component of earth’s magnetic field at a place is √3 times the horizontal component the value of angle of dip at this place is ______.
The small angle between magnetic axis and geographic axis at a place is ______.
A 10-meter wire is kept in east-west direction. It is falling down with a speed of 5.0 meter/second, perpendicular to the horizontal component of earth's magnetic field of 0.30 × 10−4 weber/meter2. The momentary potential difference induced between the ends of the wire will be:
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
Let the magnetic field on earth be modelled by that of a point magnetic dipole at the centre of earth. The angle of dip at a point on the geographical equator ______.
- is always zero.
- can be zero at specific points.
- can be positive or negative.
- is bounded.
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.
