Magnetism Question 102

Question: 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]

Options:

A) The time period decreases

B) The time period remains unchanged

C) The time period increases

D) The needle stops vibrating

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Answer:

Correct Answer: C

Solution:

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