A magnetic needle free to rotate in a vertical plane parallel to the magnetic meridian has its north tip pointing down at $22^{\circ}$ with the horizontal. The horizontal component of the earth's magnetic field at the plane is known to be $0.35 \;G$ . Determine the magnetic of the earth's magnetic field at the place.

Question

$\begin{array}{1 1} 3.8\;G \\ 38\;G \\ 0.38\;G \\ 0.038 \;G \end{array} $