A tangent galvanometer has a coil of $25$ $turns$ and a radius of $15\, cm$. The horizontal component of the earth’s magnetic field is $3\times10^{-5}\, T$. The current required to produce a deflection of $45^o$ in it is....$A$
$0.29$
$1.2$
$3.6\times10^{-5}$
$0.14$
If a brass bar is placed on a vibrating magnet, then its time period
Two tangent galvanometer coils of same radius connected in series. The current flowing produces deflection of $60^o$ and $45^o$. The ratio of number of turns in coil is
Twists of suspension fibre should be removed in vibration magnetometer so that
The time period of oscillation of a magnet in a vibration magnetometer is $1.5$ seconds. The time period of oscillation of another magnet similar in size, shape and mass but having one-fourth magnetic moment than that of first magnet, oscillating at same place will be.....$sec$
Vibration magnetometer before use, should be set