A uniform magnetic field of intensity 1T is applied in a circular region of radius 0.1 m, directed into the plane of paper. A charged particle of mass 5xx10^(-5)kg and charge q=5xx10^(-4)C enters the field with velocity 1//sqrt(3)m//s making an angle of phi with a radial line of circular region in such a way that it passes through centre of applied field the angle phi is