When you sign or file an affidavit with the court you're signing that affidavit or filing that affidavit under oath.
So you basically swear to tell the truth the whole truth and nothing but the truth on the affidavit.
If you lie on the affidavit you can be charged with perjury which can get you 30 days in jail or even 1 to 5 years in prison for lying to the court on the affidavit.
It depends on the judges decision and the case you lied about.
If it's your first offense for lying on an affidavit or committing perjury then you might get away with 30 days in jail and then on your second offense you may serve 1 year in jail or even a longer prison sentence.
Never lie in court or on an affidavit as the court can and will find out you're lying and you will be taken to jail right from the court room.