What happens to a call when the reciever is busy I have a doubt. What happens if i call a person who has an android mobile and the person is speaking to someone else. Will the android mobile store my number in its recent calls or will it not recieve the call and not store the number? Is it dependent on the network providers service or its wholly android controlled?

Thanks in advance!
Depending on the carrier of the receiver and its configuration, it is possible that your call will knock on ie. the receiver gets a sound that notifies him about an incoming call.
If he wants he can create a group call (I never heard about someone using that feature).
If that knock on feature is disabled you should go straight to the receivers mailbox and you will be listed in missed calls.