Time period in vibration magnetometer will be infinity at

Which of the following statement is not the true

A long vertical wire in which a current is flowing produces a neutral point with the earth's magnetic field at a distance of $5\, cm$ from the wire. If the horizontal component of the earth's magnetic induction is $0.18\, gauss$, then the curent in the wire is......$A$

The unit of reduction factor of tangent galvanometer is

Two short magnets having magnetic moments in the ratio $27 : 8,$  when placed on opposite sides of a deflection magnetometer, produce no deflection. If the distance of the weaker magnet is $0.12$ $m$ from the centre of deflection magnetometer, the distance of the stronger magnet from the centre is.......$m$

The radius of the coil of a Tangent galvanometer. which has $ 10 $ $turns$ is $0.1\,m. $ The current required to produce a deflection of $60°$  $({B_H} = 4 \times {10^{ - 5}}\,T)$ is.....$A$