The time period of a vibration magnetometer is $T_0$. Its magnet is replaced by another magnet whose moment of inertia is $3$ $times$ and magnetic moment is $1/3$ of the initial magnet. The time period now will be

A tangent galvanometer has $80$ turns of wire. The internal and external diameters of the coil are $19 \,cm$ and $21 \,cm$ respectively. The reduction factor of the galvanometer at a place where $H=0.32$ oersted will be $(1$ oersted $=80 \,A / m )$

Which curve may best represent the current deflection in a tangent galvanometer

The magnet of vibration magnetometer is heated so as to reduce its magnetic moment by $36\%$. By doing this the periodic time of the magnetometer will

The period of oscillation of a magnet in vibration magnetometer is $2 \,sec$. The period of oscillation of a magnet whose magnetic moment is four times that of the first magnet is...$sec$

A tangent galvanometer shows a deflection $45^o $ when $10\, mA$ current pass through it. If the horizontal component of the earth’s field is $3.6 \times {10^{ - 5}}\,T$ and radius of the coil is $10\, cm$. The number of turns in the coil is......$turns$