Question

please answer my question

Answer 1

Frequency of a magnet in a uniform magnetic field is given as = 1/2π*√mass*Field^2/length
So,
n will be proportional to Bh^2
That's directly proportional to square of magnetic field of the earth so, your Correct answer will be option C

Answer 2

Answer:

Explanation: square of frequency of magnetic needle is directly proportional to earth's magnetic field.