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प्रश्न
State two advantages of an electromagnet over a permanent magnet.
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उत्तर
- An electromagnet can produce a strong magnetic field.
- The strength of the magnetic field of an electromagnet can easily be changed by changing the current in its solenoid.
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संबंधित प्रश्न
The force on a north pole, `vecF = mvecB` , parallel to the field `vecB` . Does it contradict our earlier knowledge that a magnetic field can exert forces only perpendicular to itself?
To measure the magnetic moment of a bar magnet, one may use
(a) a tangent galvanometer
(b) a deflection galvanometer if the earth's horizontal field is known
(c) an oscillation magnetometer if the earth's horizontal field is known
(d) both deflection and oscillation magnetometer if the earth's horizontal field is not known
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The needle of a dip circle shows an apparent dip of 45° in a particular position and 53° when the circle is rotated through 90°. Find the true dip.
The magnetometer of the previous problem is used with the same magnet in Tan-B position. Where should the magnet be placed to produce a 37° deflection of the needle?
A deflection magnetometer is placed with its arms in north-south direction. How and where should a short magnet having M/BH = 40 A m2 T−1 be placed so that the needle can stay in any position?
A short magnet oscillates in an oscillation magnetometer with a time period of 0.10 s where the earth's horizontal magnetic field is 24 μT. A downward current of 18 A is established in a vertical wire placed 20 cm east of the magnet. Find the new time period.
A steel wire of length 1 has a magnetic moment m it is then bent into a semicircular arc. The new magnetic moment is
