A bar magnet takes π/10 second to complete one oscillation in an oscillation magnetometer. The moment of inertia of the magnet about the axis of rotation is 1.2 × 10–4 kg m2 and the earth’s horizontal magnetic field is 30 μT. Find the magnetic moment of the magnet.

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Given,


the earth’s horizontal magnetic field,


The moment of inertia of the magnet about the axis of rotation


the time period of a magnetometer is given by,






M = 1600Am2


1