The values of the apparent angles of dip in two planes at right angles to each other are $45^{\circ}$ and $30^{\circ}$ respectively. The true value of angle of dip at the place is ............
$\cot ^{-1}(1)$
$\cot ^{-1}(2)$
$\cot ^{-1}(3)$
$\cot ^{-1}(4)$
At an angle of $30^{\circ}$ to the magnetic meridian, the apparent dip is $45^{\circ} .$ Find the true dip :
Magnetic meridian is a
At the magnetic north pole of the earth, the value of horizontal component of earth's magnetic field and angle of dip are, respectively
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
Two normal uniform magnetic field contain a magnetic needle making an angle $60°$ with $F$. Then the ratio of $\frac{F}{H}$ is