Since the Ray deals 1d6 damage per 2 caster levels, what would be the damage if your caster level is lover than 2? 1/2, then round down. Ta-daa... 0, so 0d6 damage?
I'm pretty sure from common sense, it would be 1d6. So 1d6 on caster levels 1,2,3; 2d6 on caster levels 4 and 5; 3d6 on caster levels 6 and 7; and so on. But it would be nice to have rule to prove this.