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JEE PHYSICS MCQ: MAGNETISM AND MATTER

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A bar magnet of magnetic moment

2.5\,\mathrm{Am}^2

is free to rotate about a vertical axis through its centre. The magnet is released from rest from the east-west direction. Find the kinetic energy of the magnet as it aligns itself in the north-south direction. The horizontal component of earth's magnetic field is

0.3\,\mathrm{G}

.

View answer and explanation

Correct option: A

75 \mu \mathrm{J}

Option A (

75 \mu \mathrm{J}

) is correct because the kinetic energy equals the loss in potential energy as the magnet aligns.

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Curie temperature is the one above which A vibration magnetometer consists of two identical bar magnets placed one over the other such that they are perpendicular and bisect each other. The time period of oscillation in a horizontal magnetic field is

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\mu_{\mathrm{d}}, \mu_{\mathrm{p}}

\mu_{\mathrm{f}}

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