Q. The ratio of magnetic moments of two bar magnets is $13\ :5.$ These magnets held together in a vibration magnetometer oscillate with 15 oscillations per minute in earth’s magnetic field with like poles together. What will be the frequency of oscillations of system if unlike poles are together
A) $10\ oscillations/min$
B) $15\ oscillations/min$
C) $12\ oscillations/min$
D) $\frac{75}{13}\ oscillations/min$
Explanation
(a) $\frac{M_{1}}{M_{2}} = \frac{v_{s}^{2} + v_{d}^{2}}{v_{s}^{2} - v_{d}^{2}} \Rightarrow \frac{13}{5} = \frac{(15)^{2} + v_{d}^{2}}{(15)^{2} - v_{d}^{2}}$
$\Rightarrow v_{d} = 10\ oscillations/min$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.