Can you suggest an experiment to draw magnetic field lines of the magnetic field around the current carrying wire? 

Using electrostatic analogue, obtain the magnetic field at a distance $x$ on the perpendicular bisector of a magnetic dipole 

$\overrightarrow{\mathrm{m}}$ .For $\mathrm{x}\gg \mathrm{R}\text{, verify that }\overrightarrow{\mathrm{B}}=\frac{{\mathrm{\mu }}_0}{4\mathrm{\pi }}\frac{\mathrm{m}}{{\mathrm{x}}^3}$

A conductor has 3 segments: two starlight and of length L each and a semicircular with radius R. It carries a current I. What is the magnetic field B at point P?