What will happen if someone create a fake account and use it to increase the reputation of his original account by up voting the questions and answers? Is there any mechanism available to find out these kind of accounts?
For your first question:
Yes your account gets suspended for for period of time(some mechanism is uesd);
Is there any mechanism available to find out these kind of accounts?
Yes there is but but i think i don't know the name(No one must be knowing as because of security reason or may be too difficult to understand)