In the rectangular coordinate system xOy, the parametric equation of line l is (t is the parameter, α is the inclination angle), and the parametric equation of curve C is (β is the parameter, β∈ ). Establish a polar coordinate system with the coordinate origin O as the pole and the positive semi-axis of the x-axis as the polar axis.
(I) Write the ordinary equation of curve C and the polar coordinate equation of line l;
(II) If line l and curve C have exactly one common point P, find the polar coordinates of point P.