The correct statements are All (i), (ii), and (iii) are correct.Concept:Magnetic field:The area around a magnet where a magnetic force is experienced is called the magnetic field.It is a quantity that has both direction and magnitude, (i.e., Vector quantity).Explanation:Magnetic field around a straight wire:The nature of the magnetic field lines around a straight current-carrying conductor is concentric circles with the center at the axis of the conductor.The strength of the magnetic field is directly proportional to the current (I) through the conductor. B ? I The strength of the magnetic field is inversely proportional to the distance (r). B ? 1/rThe direction of the magnetic field lines of force around a conductor is given by Maxwells right-hand rule.??Maxwells right-hand rule:?Imagine that you are holding a current-carrying straight conductor in your right hand such that the thumb points towards the direction of the current.Then your fingers will wrap around the conductor in the direction of the field lines of the magnetic field.Statement True/ false B increases as I increasesTrue B decreases as r increasesTrueThe magnetic field line forms a concentric circle of radius r with the centre at the wireTrue