How many conformations are possible for ethane ?

A conformation is defined as the relative arrangement of atoms or groups around a central atom, obtained by the free rotation of one part of the molecule with respect to rest of the molecule. For a complete rotation of 360º, one part may rotate through any degree say 0.1º, 0.5º, 1º etc. giving rise to infinite number of relative arrangements of group (atom) around a central atom, keeping other part fixed.