The unit of reduction factor of tangent galvanometer is
Ampere
Gauss
Radian
None of these
Tangent galvanometer is used to measure
A magnetic needle is made to vibrate in uniform field $H$, then its time period is $T$. If it vibrates in the field of intensity $4H, $ its time period will be
If a brass bar is placed on a vibrating magnet, then its time period
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 strength of the magnetic field in which the magnet of a vibration magnetometer is oscillating is increased $4$ times its original value. The frequency of oscillation would then become