Consent known to be given under fear or misconception is defined under section 90 of ipc. Provisions under IPC section 90 explained here:
What is Section 90 IPC:
A consent is not such a consent as is intended by any section of this Code, if the consent is given by a person under fear of injury, or under a misconception of fact, and if the person doing the act knows, or has reason to believe, that the consent was given in consequence of such fear or misconception; orConsent of insane person. – If the consent is given by a person who, from unsoundness of mind, or intoxication, is unable to understand the nature and consequence of that to which he gives his consent; or Consent of child. – Unless the contrary appears from the context, if the consent is given by a person who is under twelve years of age
If consent is given by the prosecutrix under a misconception of fact, it is vitiated. accused committed sexual intercourse with the prosecutrix by giving false assurance that he would marry her, after she got pregnant, he refused to do so. From this it is evident that he never intended to marry her and procured her consent only for the reason of having sexual relationship with her, which act of accused falls squarely under the definition of rape as he had sexual intercourse with her consent which was consent obtained under a misconception of fact as defined under section 90 of IPC. Case: State of UP vs. Naushad, AIR 2014 SC 384
Section 90 IPC Explanation:
This section means a consent taken will not be considers as a consent under this code if it’s taken under misrepresentation or under circumstances of fear, Consent of insane person means a person who is of unsound mind or is intoxicated his consent will not be considerd as a consent under this code. Consent of child means a consent given by child under the age of 12 will not be considerd as consent under this code.