Question:
A bar magnet of magnetic moment M, is placed in a magnetic field of induction B. The torque exerted on it is
A bar magnet of magnetic moment M, is placed in a magnetic field of induction B. The torque exerted on it is
Updated On: Apr 30, 2024
- $M\times B$
- $-B\cdot M$
- $M \cdot B-$
- $M \cdot B$
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The Correct Option is A
Solution and Explanation
When a bar magnet of magnetic moment M, is placed in a magnetic field of induction B, then net force on it is
$F_R = mB + (-m )B = 0 $
while torque
$\tau = mB \times 2lsin\, \theta = MB \,sin \,\theta$
i.e. $\tau=M\times B$
$F_R = mB + (-m )B = 0 $
while torque
$\tau = mB \times 2lsin\, \theta = MB \,sin \,\theta$
i.e. $\tau=M\times B$
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Magnets are used in many devices like electric bells, telephones, radio, loudspeakers, motors, fans, screwdrivers, lifting heavy iron loads, super-fast trains, especially in foreign countries, refrigerators, etc.
Magnetite is the world’s first magnet. This is also called a natural magnet. Though magnets occur naturally, we can also impart magnetic properties to a substance. It would be an artificial magnet in that case.
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Some of the properties of the magnetic field lines are:
- The lines and continuous and outside the magnet, the field lines originate from the North pole and terminate at the South pole
- They form closed loops traversing inside the magnet.
- But here the lines seem to originate from the South pole and terminate at the North pole to form closed loops.
- More number of close lines indicate a stronger magnetic field
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- The tangent drawn at the field line gives the direction of the field at that point.