Q

A short bar magnet placed with its axis at 30° with a uniform external magnetic field of 0.25 T experiences a torque of magnitude equal to 4.5 into 10 minus 2 J. What is the magnitude of magnetic moment of the magnet?

5.3. A short bar magnet placed with its axis at 30° with a uniform external magnetic field of 0.25 T experiences a torque of magnitude equal to $4.5 \times 10 ^{-2} J$ . What is the magnitude of magnetic moment of the magnet?

Views

Given,

The angle between axis of bar magnet and external magnetic field, θ = 30°

Magnetic field strength, B = 0.25 T

Torque on the bar magnet, Τ = 4.5 x $\dpi{100} 10^{-2}$J

We know,

Torque experienced by a bar magnet placed in a uniform magnetic field is:

T = m x B = mBsin$\dpi{80} \theta$

$m = \frac{T}{Bsin\theta}$

$\implies m = \frac{4.5\times10^{-2}J}{0.25T\times sin30^{\circ}}$

$\therefore$  m = 0.36 $\dpi{80} JT^{-1}$

Hence, the magnitude of the moment of the Bar magnet is 0.36 $\dpi{80} JT^{-1}$.

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