At a certain place, the horizontal component of earth's magnetic field is $\sqrt 3 $times the vertical component. The angle of dip at that place is....$^o$
$60$
$45$
$90$
$30$
The direction of the null points is on the equatorial line of a bar magnet, when the north pole of the magnet is pointing
The torque on a bar magnet due to the earth's magnetic field is maximum when the axis of the magnet is
Due to the earth's magnetic field, charged cosmic ray particles
A bar magnet is situated on a table along east-west direction in the magnetic field of earth. The number of neutral points, where the magnetic field is zero, are
The magnetic field of earth is due to