A vibration magnetometer placed in magnetic meridian has a small bar magnet. The magnet executes oscillations with a time period of $2\, sec$ in the earth's horizontal magnetic field of $24$ $microtesla$ . When a horizontal field of $18$ $microtesla$ is produced opposite to the earth's field by placing a current carrying wire, the new time period of magnet will be….$s$

A short bar magnet placed in a horizontal plane has its axis aligned along the magnetic north-south direction. Null points are found on the axis of the magnet at $14\; cm$ from the centre of the magnet. The earth's magnetic field at the place is $0.36\; G$ and the angle of $dip$ is zero.If the bar magnet is turned around by $180^o$, where will the new null points (in $cm$) be located?

The length of a magnet is large compared to its width and breadth. The time period of its oscillation in a vibration magnetometer is $2 \,s. $ The magnet is cut along its length into three equal parts and three parts are then placed on each other with their like poles together. The time period of this combination will be

The unit of reduction factor of tangent galvanometer is

When $\sqrt 3 $ $ampere$ current is passed in a tangent galvanometer, there is a deflection of $ 30° $ in it. The deflection obtained when $3$ $ampere$ current is passed, is…..$^o$