The relations amongst the three elements elements earth's magnettic fleld, namely horizontal component $H$, vertical component $V$ and dip $\delta$ are, $(  B_{E}=$ total magnetic fleld) 

At a place, the magnitudes of the horizontal component and total intensity of the magnetic field of the earth are $0.3 $ and $ 0.6$  Oersted respectively. The value of the angle of dip at this place will be.....$^o$

A current carrying coil is placed with its axis perpendicular to $N-S$ direction. Let horizontal component of earth's magnetic field be $H_0$ and magnetic field inside the loop be $H$. If a magnet is suspended inside the loop, it makes angle $\theta $ with $H$. Then $\theta =$

The vertical component of the earth's magnetic field is zero at a place where the angle of dip is.....$^o$

At a place, if the earth's horizontal and vertical components of magnetic fields are equal, then the angle of dip will be.......$^o$

If $\theta _1$ and $\theta_2$ be the apparent angles of dip observed in two vertical planes at right angles to each other, then the true angle of dip $\theta$ is given by