Question

At a certain place, a magnet makes $30$ oscillations/min. At another place where the magnetic field is double, its time period will be :

• A. $4sec$
• B. $2sec$
• C. $0.5sec$
• D. $\sqrt{2}$ sec

Answer 1

The correct option is D $\sqrt{2}$ sec

The time period of oscillation is given by

$T=2\pi \sqrt{\frac{I}{MB}}$

$\frac{T_2}{T_1}=\sqrt{\frac{B_1}{B_2}}$

$T_2=\sqrt{\frac{1}{2}}\times 2$

$T_2=\sqrt{2}$ sec