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A magnet of magnetic dipole moment 5.0 A m2 is lying in a uniform magnetic field of 7 x 10⁻⁴ T such that its dipole moment vector makes an angle of 30° with the field. The work done in increasing this angle from 30° to 45° is about _______ J.(A) 5.56 x 10⁻⁴ (B) 24.74 x 10⁻⁴ (C) 30.3 x 10⁻⁴ (D) 5.50 x 10⁻³ |
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Answer» The TOTAL work done in rotating the DIPOLE from to is .Option (A) is correct.Explanation:The work done in rotating from INITIAL ANGLE to a final angle is given by.where, = torque exerted on the magnet due to the MAGNETIC field.We know,where, = dipole moment of the magnet. = magnetic field in which the magnet is placed. = angle between and .Therefore, the work done in rotating from initial angle to a final angle is given byGiven:....Putting these values in above expression of required work done, we get, Thus, the correct option is (A). |
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