A tangent galvanometer has a coil with $50$ $turns$ and radius equal to $4$ $cm$. A current of $0.1 $ $A$ is passing through it. The plane of the coil is set parallel to the earth's magnetic meridian. If the value of the earth's horizontal component of the magnetic field is $7 \times {10^{ - 5}}$ $tesla$ and  ${\mu _0} = 4\pi \times {10^{ - 7}}\, weber/amp \times m$, then the deflection in the galvanometer needle will be.....$^o$

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

In a tangent galvanometer a current of $0.1 \,A $ produces a deflection of $30^o$. The current required to produce a deflection of $60^o$ is......$A$

The time period of oscillation of a bar magnet suspended horizontally along the magnetic meridian is $T_0$. If this magnet is replaced by another magnet of the same size and pole strength but with double the mass, the new time period will be

The magnetic needle of a tangent galvanometer is deflected at an angle $30^o$ due to a magnet. The horizontal component of the earth's magnetic field is $0.34 \times 10^{-4}\, T$ which is along the plane of the coil. The magnetic field due to magnet is

Before using the tangent galvanometer, its coil is set in