MCQ
At two places $A$ and $B$ using vibration magnetometer, a magnet vibrates in a horizontal plane and its respective periodic time are $2$ sec and $3 \mathrm{sec}$ and at these places the earth's horizontal components are $H$ and $H$ respectively. Then the ratio between $H$ and $H$ will be
- ✓$9: 4$
- B$3: 2$
- C$4: 9$
- D$2: 3$