Hi Aruna,
this is my first robot.
Good job!Very confident when it detects a flame with direct line of sight.
Things to improve:
1) On the second candle, it seems to be baffled by detecting the flame, but getting close to the blue(?) obstacle, the flame is covered by that and sort of confuse the decision making robot.
2) There is a bit pushing of a shoe
3) It seems to like dark places and you seem to disprove of it (isn't it allways the case with "kids" and their "parents"
Suggestions to deal with those issues is, In reverse order:
3) Simple light detectors with an LDR in a short tube pointed forwards and backwards (or up) and a bit of code should do.
2) Bump detectors (can be made very simple).
1) A better algorithm for when it gets baffled. You could make it try twice and if it fails, move some distance before trying to detect a flame again.
I especially like the little pan it makes, when it detects the flame isn't out after a short time (it could be made into a slower pan starting to one side and sweeping slowly across where it detect the flame, to put the fire out a bit faster.
Did you use State Machine programming?
That said... Very very convincing, I hope you get full marks for that - and giving that it's your first-born, I'd say you have potential for some serious robotics in the future