The Indian Penal Code, 1860 defines Perjury in Chapter IX "OF FALSE EVIDENCE AND OFFENCES AGAINST PUBLIC JUSTICE" under Section 191. The punishment for the offence of Perjury is defined under section 193 of Indian Penal Code, 1860 as SEVEN YEARS of imprisonment. The procedure in dealing with cases mentioned u/s 191 of Indian Penal Code, 1860 are dealt in Chapter XXVI of The Code of Criminal Procedure, 1973 under section 340.
The mere fact that a person has made a contradictory statement in a judicial proceeding is not by itself always sufficient to justify a prosecution under Sections 199 and 200 of the Indian Penal Code (45 of 1860) (hereinafter referred to as "the IPC"); but it must be shown that the defendant has intentionally given a false statement at any stage of the judicial proceedings or fabricated false evidence for the purpose of using the same at any stage of the judicial proceedings.
However, you cannot directly assume that she's lying in her petiton as it is possible that she took up a job as a teacher within a span of the first and the last petition. Thus if you plan on filing a perjury case against her, please find strong evidence that supoorts the fact that she lied in her petition or else you can be sued for defamation and filing a false complaint.
Regards,
Anaita Vas