A tangent galvanometer has a coil of $100$ $turns$ and a radius of $20\,cm$. The horizontal component of the earth's magnetic field is $B_H = 3\times10^{-5}\,T$. Find the current which gives a deflection of $45^o$.

Tangent galvanometer is used to measure

Two bar magnets of the same mass, length and breadth but magnetic moments $M$ and $2\,M$ respectively, when placed in same position, time period is $3 \,sec$. What will be the time period when they are placed in different position

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?

Twists of suspension fibre should be removed in vibration magnetometer so that

Which of the following statement is not the true