The period of oscillation of a magnet is $2 \, s$. When it is remagnetised so that the pole strength is $4$ times its original value,its new period will be......$s$.

If a brass bar is placed on a vibrating magnet, then its time period

$A$ short bar magnet is placed in the magnetic meridian of the earth with its north pole pointing towards the geographic north. Neutral points are found at a distance of $30 \, cm$ from the magnet on the East-West line, drawn through the center of the magnet. The magnetic moment of the magnet in $A \cdot m^2$ is close to: (Given $\frac{\mu_0}{4\pi} = 10^{-7} \, T \cdot m/A$ and $B_H = 3.6 \times 10^{-5} \, T$)

$A$ magnetic needle of magnetic moment $6.7 \times 10^{-2} \ Am^2$ and moment of inertia $7.5 \times 10^{-6} \ kgm^2$ is performing simple harmonic oscillations in a magnetic field of $0.01 \ T$. Time taken for $10$ complete oscillations is.....$s$

The ratio of magnetic moments of two bar magnets is $13 : 5$. These magnets are held together in a vibration magnetometer and are allowed to oscillate in the Earth's magnetic field. When like poles are together,$15$ oscillations per minute are made. What will be the frequency of oscillation of the system if unlike poles are together? (in $oscillations/min$)

$A$ magnet makes $20$ and $15$ oscillations in $1$ minute at two places where the angles of dip are $30^{\circ}$ and $60^{\circ}$ respectively. What is the ratio of the total magnetic fields at these two places?