A short bar magnet of magnetic moment $5.25 \times 10^{-2}\;J/T$ is placed with its axis perpendicular to the earth's field direction . At what distance from the center of the magnet , the resultant field is inclined at $45^{\circ}$ with earth's field at the place is given to be $0.42\;G$ Ignore the length of the magnet in companion to the distance involved

Question

$\begin{array}{1 1} 6.3\;cm \\ 63\;cm \\ 0.63 \;cm \\ 6.3 \;m \end{array}$