The angle of dip at a place is $60°$. At this place the total intensity of earth's magnetic field is $0.64 $ $units$. The horizontal intensity of earth's magnetic field at this place is......$ units$

Define angle of dip. and Write the definition of declination.

At a point on the surface of the earth, the value of the horizontal component of earth's magnetic field is equal to value of vertical magnetic component of earths magnetic field the angle of dip is

A very small magnet is placed in the magnetic meridian with its south pole pointing north. The null point is obtained $20\, cm $ away from the centre of the magnet. If the earth's magnetic field (horizontal component) at this point be $0.3$ $gauss$, the magnetic moment of the magnet is

The magnetic field due to the earth is closely equivalent to that due to

Assume the dipole model for earth’s magnetic field $\mathrm{B}$ which is given by

${{\rm{B}}_{\rm{v}}} = $ vertical component of magnetic field

$ = \frac{{{\mu _0}}}{{4\pi }}\frac{{2m\,\cos \theta }}{{{r^3}}}$

${{\rm{B}}_H} = $ Horizontal component of magnetic field

${{\rm{B}}_H} = \frac{{{\mu _0}}}{{4\pi }}\frac{{m\,\sin \theta }}{{{r^3}}}$

$\theta $ $= 90^{°}$ -latitude as measured from magnetic equator.

$(a)$ Find loci of points for which : dip angle is zero;