A straight long wire is carrying current I. The ratio of magnetic field due to this wire at perpendicular distance 2 cm and 5 cm respectively from the wire is

Two wires with current 3A and 1.5A are enclosed in a circular loop P. Third parallel wire with current 1A is situated outside the loop as shown. All the wires are perpendicular to the plane of the circular loop. The value of $\oint \vec{B} \cdot \vec{dl}$ around the loop is ($\mu_0 = $ permeability of free space)

In the following figure, the magnitude of the magnetic field at point 'O' will be

The ratio of magnetic field at the centre of the current carrying circular loop and its magnetic moment is '$x$'. When both the current and radius are tripled, then the ratio will be