• # question_answer A magnetic needle suspended by a silk thread is vibrating in the earth's magnetic field. If the temperature of the needle is increased by 500°C, then                                                           [MNR 1994] A)            The time period decreases B)            The time period remains unchanged C)            The time period increases D)            The needle stops vibrating

$T\propto \frac{1}{\sqrt{M}}$. Since magnetic moment decreases with increase in temperature hence time period T increases.