Question

A magnet is suspended in such a way that it oscillates in the horizontal plane. If it makes 20 oscillation per minute at a place where dip angle is and 15 oscillations per minute at a place where dip angle is . The ratio of total earths net magnetic field at the two places is

Answer 1

Answer:

Let the total magnetic fields due to earth at two places be B1 and B2 . If the horizontal components be (BH)1 and (BH)2 respectively then

(BH)1 = B1 Cos 30° and (BH)2 = B2 Cos 60° Here T1 = 3 sec. and T2 = 4 sec.