Thanks a lot Seana and Dee for your replies!!
I plucked a couple of hair of the same thickness and length to see what's happening...it looks the same as zapped hair. I think it's new growth because I had almost cleared the area before. Maybe the hair didn't take complete hold and hence does have an obvious root. But it's shaft end is kinda whitish.
I'll start reading again on hair growth phases and all related stuff that there is... maybe most of my doubts are just confusion in my head. I never liked bio and the names of the phases just add to my inability to understand
I have noticed following things so far,
1. Thick hair (which has been regularly plucked) has black bulb as a root with gel like tube on the shaft. After zapping you can see both the bulb and gel.
2. Hair which hasn't been plucked, and is thinner than above har has white root which is visible after zapping.
3. The newly growing hair has whitish shaft end but no obvious root.